Answer – According to the question – Mass of trolley is 0.5 kg Velocity is 2 m / s The potential energy of the compressed spring is totally converted into kinetic energy when it is released. The...
(a) the kinetic energy possessed by the bullet, and (b) the average retarding force offered by the target. Solutions: According to the question – Mass of bullet is 50 g Or, M = 0.05 kg Velocity is...
(a) carrying the box waits for 5 minutes for a bus? (b) runs carrying the box with a speed of 3 m/s-1 to catch the bus? (c) raises the box by 0.5 m in order to place it inside the...
Solutions: According to the question – Momentum is P = 500 gcm / s P = 0.005 kgm / s Mass of ball is 50 g Or, m = 0.05 kg Using the expression of kinetic energy, we have – Kinetic energy of the ball...
(i) the kinetic energy and (ii) the speed of the body. Solutions: According to the question – Mass of body is 60 kg Momentum is p = 3000 kgm / s (a) using the expression of kinetic energy, we have...
(i) the work done by the engine and (ii) its power. (g =10 m/s-2) Solutions: According to the question, we are given – u is initial speed given, = 36 km / h = 36 × 1000m / 3600s u = 10 m / s...
Solutions: According to the question – Let initial Mass be denoted by m1 = 10 kg and Velocity, v1 is 20 m / s Then, final mass is m2 = 2 × 10 kg and Velocity, v2 is 20 / 2...
(i) its kinetic energy and (ii) its momentum. Solutions: According to the question – Mass of cannon ball is 500 g = 0.5 kg Speed, v is 15 m / s (a) from the expression of the kinetic energy of ball,...
Solutions: According to the questions – Mass of ball is 0.5 kg Initial velocity is 5 m / s Using the expression of the kinetic energy, we have – Initial kinetic energy = 1 / 2 × mass ×...
Solutions: We know that – KE = 1 / 2 × mass × (velocity)2 It can be inferred that KE α v2 So, KE1 / KE2 = v12 / v22 Upon substituting the given values in the equation above KE1 /...
Solutions: According to the question – Velocity of first body v1 is v Velocity of second body, v2 is 2v Kinetic energy is directly proportional to the square of the velocity...
Solutions: We know that, the kinetic energy is directly proportional to the square of velocity. Therefore, velocity is reduced is half its original value. Applying this to our problem we get – ΔK =...
Solutions: If the speed is halved while the mass remains the same, the kinetic energy drops. Because kinetic energy is related to velocity squared, it is one-fourth.
Solutions: According to the question – Mass is m = 1 kg Velocity is v = 10 m / s Therefore, the expression for kinetic energy is given by – Kinetic Energy = 1 / 2 × mass × (velocity)2 Upon...
(a) What is the work done by the force F in moving the block A, 5m along the slope?(b) What is the increase in potential energy of the block A?(c) Account for the difference in the work done by the...
(g= 9.8m s-2). Solutions: According to the question – Mass of man is 50 kg Height of ladder is h2 = 10 m (i) Using the expression for work done, we have Work done by man = mgh2 = 50 × 9.8 × 10...
Solutions: According to the question – Mass of water is m = 50 kg Height is h = 15 m Expression for the gravitational potential energy is = mgh = 50 × 10 × 15 = 7500 J
(Take g=10 N kg-1). Solutions: According to the question, mass of the boy is 25kgf and height of the floor from the ground is 3m and ground ia at a height of 9m. Expression for the Force of gravity...
(Take g=10 N kg-1). Solutions: According to the question, mass of the boy is 25kgf and height of the floor from the ground is 3m and ground ia at a height of 9m. Expression for the Force of gravity...
Solutions: According to the question – Mass is 0.5 kg Energy is 1 J Expression for gravitational potential energy is mgh Therefore upon substituting the values, we get – 1 = 0.5 × 10 × h à 1 =...
(i) the loss in potential energy of the body, (ii) the total energy possessed by the body at any instant? (Take g = 10 ms-2). Solutions: According to the question – (i) Mass of the body is M =...
Solutions: According to the question – Gravitational potential energy is 14700 J Expression of force of gravity is mg Therefore, we have – = 150 × 9.8 N/kg = 1470 N We have, gravitational potential...
Solutions: According to the question, Mass, m is 1 kg Height, h is 5 m Expression of gravitational potential energy is mgh So, we have = 1 × 10 × 5 = 50 J
Solutions: According to the question, Height H1 is h Height H2 is 2h Mass of body 1 is m Mass of body 2 is m So, using the expression for the potential energy we have – Gravitational...
(Take g = 10 m s-2). Solutions: According to the question, Expression for total kinetic energy at mean position is 1 / 2 mv2 Therefore, Kinetic energy = 1 / 2 m × 52 Energy lost is 1 / 2 m ×...
(g=10 m s-2). Solutions: According to the question, We know that the expression of Potential energy is mgh Efficiency is 40% Useful work done is equal to 40% of potential energy = 40 / 100 (mgh) =...
(a)Calculate the change in the gravitational potential energy of the skier between A and B. (b)If 75% of the energy in part (a) becomes the kinetic energy at B, calculate the speed at which the...
(a) Taking g = 10m/s2, calculate: (i) the potential energy possessed by the ball when it is initially at rest. (ii) the kinetic energy of the ball just before it hits the ground? (b)What...
(a) the potential energy at the greatest height, (b) the kinetic energy on reaching the ground (c) the total energy at its half waypoint. Solutions: (a) Potential energy at maximum height = initial...
Solutions: According to the question, potential energy at the maximum height = initial kinetic energy = 1 / 2 mv2 = 1 / 2 × 0.20 × 20 × 20 = 40J
(a) It has only the kinetic energy at its each position. (b) It has the maximum kinetic energy at its extreme position. (c) It has the maximum potential energy at its mean position. (d) The sum of...
A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h. The correct statement is: a. Potential energy of the ball at the ground...
(a) the extreme position, (b) the mean position, and (c) between the mean and extreme positions. Solutions: (a) Potential energy is the energy held by the bob of a simple pendulum in its most...
(i) A, (ii) B and (iii) C? Solutions: I At point A, the pendulum has the most kinetic energy, whereas its potential energy is zero. As a result, K = mgh and U = 0 (ii) At position B, the potential...
Solutions: When the bob swings from A to B, the kinetic energy declines and the potential energy increases until it reaches its maximum at B, where it is momentarily at rest. From B to A, the...
(a)At the point from where it falls. (b)While falling (c)On reaching the ground. Solutions: (a) Potential energy is the energy that the body possesses at the point when it falls. (b) The body's...
Solutions: When a body is thrown vertically upwards, its kinetic energy is converted to potential energy, and its velocity is reduced to zero.
Solutions: The motion of a simple pendulum and the motion of a freely falling body are two examples of systems in which the mechanical energy of the system remains constant.
When there is no frictional forces, the law of conservation of mechanical energy asserts that anytime potential and kinetic energy are exchanged, the total mechanical energy remains constant, i.e. K...
Solutions: Energy cannot be created or destroyed, according to the principle of conservation of energy. It only transforms from one state to the next.
a. Electrical to mechanical b. Electrical to chemical c. Chemical to mechanical d. Chemical to electrical Solutions: In an electric cell while in use, the change in energy is...
a. Kinetic energy b. Potential energy c. Solar energy d. Heat energy Solutions: A body at a height possesses (b) potential energy.
The conversion of part of energy into an undesirable form is called…………….. Solutions: degradation of energy.
Solutions: During the conversion of energy from one form to another, a portion of it is changed to an undesired form or lost to the environment as a result of friction or radiations, and this energy...
Solutions: During the conversion of energy from one form to another, a portion of it is changed to an undesired form or lost to the environment as a result of friction or radiations, and this energy...
Solutions: No. Because whenever energy is totally converted into another useful form, a portion of the energy is dissipated as heat, which is lost to the environment.
Solutions: Nuclear fission is the process used for producing electricity from nuclear energy.
(j)A petrol engine of a running car (k)An electric iron (l)A ceiling fan (m)An electromagnet. Solutions – j) Chemical energy is converted to mechanical energy. (k) Heat energy is converted from...
(g)A solar cell (h)Biogas burner (i)An electric cell in a circuit (g) Electrical energy is converted from light energy. (h) Chemical energy is converted to thermal energy. (i) Chemical energy is...
(d)Washing machine (e)A glowing electric bulb (f)Burning coal Solution – (d) Mechanical energy is converted from electrical energy. (e) Light energy is converted from electrical energy. (f) Chemical...
(a)Loudspeaker (b)A steam engine (c)Microphone Solution – (a) Electrical energy is converted into acoustic energy. (b) Thermal energy is converted to mechanical energy. (c) Electrical energy is...
(a) the unwinding of a watch spring (b) a loaded truck when started and set in motion, (c) a car going uphill, (d) photosynthesis in green leaves, (e) charging of a battery,...
Solutions: The six different forms of energy are (a) Solar energy (b) Heat energy (c) Light energy (d) Hydro energy (e) Nuclear energy (f) Mechanical energy
Solutions: Kinetic energy Kinetic energy is the energy of moving particles in an item or system. It is by the virtue of the motion.
Solutions: The kinetic energy is the only form of energy in which potential energy can change.
Solutions: The potential energy held in water at a height is converted to kinetic energy during the fall of water from a height. When water strikes the ground, some of its kinetic energy is...
Solutions: The kinetic energy in the stone is transformed to potential energy when it is hurled higher. At the height of its speed, all of its kinetic energy is transformed to potential energy....
Solutions: The compressed spring has elastic potential energy due to its compacted state. When the spring is released, its potential energy transforms into kinetic energy, which works on the ball...
Solutions: When a bow's string is pulled, the work done is stored in the bow's deformed condition, which is represented by its elastic potential energy. The potential energy of the bow is converted...
(a)The kinetic energy of a body is the energy by virtue of its _______. (b)The potential energy of a body is the energy by virtue of its _______. Solutions: (a) motion (b) position
Solutions: Potential energyKinetic energyIt can change only in the form of kinetic energy.It can change into any other formIt does not depend on the speed of the bodyIt depends on the speed of the...
Solutions: The three forms of kinetic energy are: (i) Translational kinetic energy Example: A car moving in a straight path. (ii) Rotational kinetic energy Example: A rotational wheel (iii)...
Solutions: Kinetic energy is related to momentum and mass as p = √2mk Because both bodies have the same kinetic energy, momentum is proportional to the square root of mass. Body B has a bigger mass...
Solutions: The relationship between kinetic energy and momentum is K = p2 / 2m where p is momentum and k is kinetic energy The momentum of both masses is the same, p. The kinetic energy k is...
Solutions: Allow a mass m to move at an initial velocity u. When force is applied to the body in its motion direction, an acceleration ‘a' is produced, and the body's velocity changes from u to v...
Solutions: According to the work theorem, the work done by a force in the same direction on a moving body is equal to the increase in its kinetic energy
(b) Show that the quantity 2K/v2 has the unit of mass, where K is the kinetic energy of the body. Solutions: According to the question, (a) The expression for kinetic energy of a body of mass m...
Solutions: W = force of gravity (mg) displacement (h) = mgh The work done on the body while elevating it to a height h is W = force of gravity (mg) displacement (h) = mgh When the body is at a...
Solutions: W = force of gravity (mg) displacement (h) = mgh The work done on the body while elevating it to a height h is W = force of gravity (mg) displacement (h) = mgh When the body is at a...
Solutions: The gravitational potential energy of a body is defined as - the potential energy possessed by that body as a result of the earth's force of attraction on it. The work done in elevating a...
Solution – Even when the body is not in action, it has potential energy. A stone at a height, for example, has gravitational potential energy due to its elevated location.
Solutions: The potential energy of a body at rest is described as - the energy possessed by the body due to its position, size, and shape. The following are the several types of potential energy:...
Solutions: (a) A moving cricket ball ---------------- Kinetic energy (K) (b) A compressed spring ------------------------- Potential energy (U) (c) A moving bus ---------------------- Kinetic energy...
Solutions: Wound up watch spring possesses an elastic potential energy. The energy accumulated as a result of applying a force to deform an elastic item is known as elastic potential energy. Until...
Solutions: The two forms of mechanical energy are Kinetic energy and potential energy. The stored energy in any object or system as a result of its position or arrangement of elements is known as...
Solutions: According to the question, both the people carry same weight of water to the same height but in different time periods. (a) (i) Since, both the people carry same weight of water to the...
(a) Compare: (i) the work done, and (ii) the power developed by them. (b) Calculated: (i) the work done, and (ii) the power developed by each man. Take g = 10N kg-1. Solutions: According to the...
(i) the work done, and (ii) the power developed by them. Take g = 10 N kg-1. Solutions: According to the question – Weight of the boy is 40kgf and weight of the girl is 20kgf (i) Work done can be...
(i) work done and (ii) power developed by the persons A and B. Solutions: According to the question, mass of the person is 50kg and time taken is also given. (i) The work done by two persons A and B...
(i) the work done, and (ii) the power spent. Solutions – According to the question, mass of the boy is 350N and displacement is total distance covered in 30 steps, which is – S = 30 × 20 cm= 600 cm...
Solutions: Power exerted by Rajan due to force can be determined by using the following relation – P = Fv = 150 × 10 Therefore, power = 1500 W
Solutions: According to the question – Power is 40 kW Force is 20,000 N Expression for power is – Power = force × velocity Upon re-arranging we get the expression – Velocity = power / force = 40 kW/...
Solutions: According to the question – Force is 1000 N Velocity is 30 m/s Expression for power is – P = force × velocity = 1000 × 30 = 30,000W Power = 30 kW
(a) The work done by the pump, (b) The power at which the pump works, and (c) The power rating of the pump if its efficiency is 40%. (Take g= 10m s-2). Solutions: According to the question, mass of...
(Take g= 10N kg-1 and density of water =1000kg m-3). Solutions: According to the question – Volume of water is 50 L Which when expressed in m3 becomes 50 × 10-3 m3 Density of water...
Express your answer in (i) kWh (ii) joule. Solutions: Expression for the Energy consumed is as follows – Energy = power × time (i) Substituting values from the questions and we have – Energy = 3 kW...
(i) the energy spent by the machine. (ii) the power of the machine if it is 100% efficient. Solutions: (i) Energy spent by machine is simply the work done by the machine and we know that the...
(i) the work is done, and (ii) the power developed by him. Take g =10N/kg-1. Solutions: According to the question, mass is 200kgf and the displacement is 2.5m. Total time taken is 5 seconds. So, we...
Solutions: According to the question – Work done by man is 6.4 kJ 64 m is the distance moved (i) Then, the work done by the man is Work = Force × distance moved in direction of force Upon...
(i) The force of gravity acting on the boy, (ii)The work done by him against gravity, (iii)The power spent by the boy. (take g= 10ms-2) Solutions: According to the question – Mass of a boy is 40 kg...
(i) in the direction of force, (ii) at an angle of 60o with the force, and (iii) normal to the force. (g= 10Nkg-1) Solutions: According to the question – Force acting on the body is 10 kgf = 10...
a. Power b. Force c. Energy d. None of these Solutions: kWh is the unit of (c) energy
a. 1000 W b. 500 W c. 764 W d. 746 W Solutions: One horsepower is equal to (d) 746 W
Solutions: Yes, there is no energy transfer when the body is acted upon by a force normal to the displacement. When the body moves in a circular direction and the work done is zero, the force is...
(a) kWh (b) kW (c) Wh (d) eV Solutions: (a) Energy is measured in kWh (b) Power is measured in kW (c) Energy is measured in Wh (d)...
Solutions: The unit of work is watt-hour (Wh) while unit of power is the watt (W). Since power × time = work or energy
(b) How is horsepower related to the S. I. unit of power? Solutions: (a) The physical quantity measured in terms of horsepower is Power. (b) It is related to the S.I unit watt by the relation – 1...
Solutions: The S.I unit of power is the watt (W) The power spent is said to be 1 watt, if 1 joule of work is done in 1 second.
Solutions: Work 1) The product of force and displacement in the force's direction equals the work done by the force. 2) The amount of work done is independent of time. 3) The joule is a SI unit of...
Solutions: EnergyPowerThe energy of a body is its capacity to do work.Power of a source is the rate at which energy is supplied by itEnergy spent does not depend on timePower depends on the time in...
Solutions: The quantity of power consumed by a source is determined by two factors: (i) The amount of work done by the source and (ii) the amount of time it takes the source to do the job. Consider...
Solutions: The energy spent (or work done) by a source of power 1 kW in 1 h is known as kilowatt-hour. 1 kWh = 3.6 × 106 J
Solutions: Heat energy is measured in calorie. 1 calorie = 4.18 joule
(a) 1 J = _____ calorie. (b) 1 kWh = ______ J. Solutions: (a) 1 J = 0.24 calorie (b) 1 kWh = 3.6 × 106 J
Solutions: Electron volt (eV) is used to measure the energy of atomic particles. It is given by – 1 eV = charge on...
Solutions: The term "energy" is defined as "the capacity of a body to perform work." The Joule is the SI unit of energy.
(a) What is the work done by the boy against the force of gravity? (b) What would have been the work done if he uses a lift in climbing the same vertical height? Solutions: Allow a boy with mass m...
Solutions: Allow a body of mass m to fall vertically or in an inclined plane from a height h. Consider a hill, a slope, or a staircase. The force of gravity acting vertically downwards on the body...
Solutions: We know that, 1 joule = 1N × 1m Also, 1 N = 105 dyne and 1 m = 102 cm Therefore, we have – 1 joule = 105 dyne × 102 cm = 107 dyne × cm = 107 erg Hence,...
Solutions: The Joule is the SI unit of work. One joule of work is done when a force of one newton displaces a body over a distance of one metre in its direction.
Solutions: The C.G.S unit of work is erg and S.I unit of work is Joule. We know that the relation between joule and erg is given by the expression – 1N × 1m = 1 joule Also, 1 N = 105 dyne...
Solutions: When a coolie carries a weight while walking on the ground and the force of gravity works vertically downward, the displacement is in the horizontal direction. As a result, the work done...
Solutions: When a fielder makes a catch, the labour he does is negative because the force he applies is in the opposite direction of the ball's movement.
Solutions: The capacity to do work is energy, and the amount of energy expended equals the amount of work completed. The coolie X will do more work because his work involves a change in potential...
(a) A man pushes a wall. (b) A coolie stands with a box on his head for 15 min. (c) A boy climbs up 20 stairs. Solutions: (a) Work is done by a man (b) No, work is not done by a coolie (c) Yes, work...
Solutions: The work done by gravity is zero because the force of gravity acting on the satellite is perpendicular to the satellite's displacement.
Solutions: When a body moves in a circular path, no work is done since the force on the body is directed towards the circular path's centre (the centripetal force acts on the body), and the...
Solutions: When a body is moved in the opposite direction of the force operating on it, work is done against the force.
Solutions: I If the body's displacement is in the direction of force, the work done is positive; Therefore, W = F S. When a coolie elevates a load against gravity, the work done by the coolie on the...
Solutions: Two conditions When the work done is zero are – (i) Condition of no displacement, S = 0 and (ii) Condition of normal displacement θ = 900
(a) Write the expression for the work done by the force. (b) What should be the angle between force and displacement so that the work done is (i) zero, (ii) maximum? Solutions: (a) W = F S cos θ...
(i) force is in direction of displacement, (ii) force is at an angle to the direction of displacement? Solution : (i) W = F × S This expression gives the work done when force is in direction of...
Solution – When a force is supplied to a body that causes it to move, the work is said to be completed. It's a scalar value.