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PHYSOL EXAMINATION SERIES, WORK ENERGY & POWER, SUNDAY 18-07-2021 @ 5.00pm, PES05, TIME: 1 HOUR, MAXIMUM SCORE:30, General Instructions to Students, There is a 'cool-off time' of 15 minutes in addition to maximum writing time, • Use cool-off time to get familiarise with questions and their answers, • Read questions and instructions carefully before answering, Calculations, figures, graphs should be shown in the answer sheet itself, You can write any number of questions fully or partially to get a maximum, Score of 30, • Electronic devices except non-programmable calculators are not allowed in the, examination, Questions from 1 to 4 carries 1 score, 1 kWh is the unit of., 1, 2 Horse power is the unit of, 1, 3 Gravitational force is a, .force (Conservative, Non Conservative), 1, 4 1 joule =, erg, 1, Questions from 5 to 8 carries 2 score HSPTA, 5 Two bodies of masses m, and m2 have the same linear momentum. What is the ratio of their, kinetic energies ?, 6 A ball at rest is dropped from a height of 12 m. It loses 25% of its kinetic energy on striking, the ground. Find the height at which it bounces., 2, 7 Total energy of a system is always conserved, no matter what internal or external forces on, the body are present., a)State true/ false., b)Justify your answer., 1, 1, 8 A car and a truck have the same kinetic energies at a certain instant while they are moving, along two parallel roads., a)Which one will have greater momentum?, b)If the mass of truck is 100 times greater than that of the car, find the ratio of the velocity, of the truck to that of the car., 1, 1, Questions from 9 to 12 carries 3 score, 9 A man tries to lift a mass 200kg with a force 100N., a)Is he doing work? Explain., b)If yes, find the amount of work done. if no, find the force required to lift it., c)If it is lifted to 2m in 10 s, Find power., 1, 1, 1, PHYSOL-The solution for learning Physics, Prepared by Higher Secondary Physics Teachers Association Malappuram

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10 a)A truck and a car are moving with the same kinetic energy are stopped by applying same, retarding force by means of brakes. Which one will stop at a smaller distance., b)How the work energy theorem helps us to generate electricity?, 2, 1, 11 A motor pump can fill water in a tank of 40 m3 at a height 5m from the ground in 30, minutes. Find the power required for this process? Given density of water is 1000 kg/m³, 12 a)Write the equation for potential energy of a spring., b)A spring extended to a length x, the energy stored is E. If it is extended a distance 2x, find, the energy developed in the spring in terms of E., 1, 2, Questions from 13 to 16 carries 4 score, 13 Power is the rate at which work is done., a)Express power in terms of force and velocity., b)An elevator carrying the maximum load of 1800 kg is moving up with a constant, speed of 2 ms The frictional force opposing the motion is 4000 N. Determine the, minimum power delivered by the motor to the elevator., c)Express your above answer in horse power?, 1, 2, 1, 14 a)An artificial satellite is revolving around the earth.we are reducing the radius of the, 1, orbit. The speed of the satellite increases. Why?, b)Show that the potential energy of a body is completely converted into kinetic, energy during its free fall under the gravity., c)A man carefully brings down a glass sheet from a height 2 m to the ground. The work, done by him is, a.negative, b.zero, 2, 1, c.positive, d.unpredictable, O HSPTA, 15 Force is required to lift a body from the ground to a height h and work is measured as the, product of force and magnitude of displacement., a) Name the energy possessed by the body at maximum height. Write an equation for it., b) A man of mass 60 kg carries a stone of mass 20 kg to the top of a multi-storied building, of height 50m. Calculate the total energy spent by him? (9.8m/s 2), 2, 16 The Bob of a pendulum is released from a horizontal position. If the length of the pendulum, is 1.5 m., 1.5 m, 1.5 m, a)Energy at A is entirely, b)What is the speed with which the Bob arrives at the lowermost point, given that it, dissipated 5% of it's initial energy against air resistance?, 1, PHYSOL-The solution for learning Physics, Prepared by Higher Secondary Physics Teachers Association Malappuram

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Questions 17 and 18 scores 5 each, 17 a. State and prove that the law of conservation of energy for a freely falling body., b. Draw graphically the variation of kinetic energy and potential energy with the height of, the body in the above case., 2, 18 The scalar product of force and displacement gives work. It can be negative, zero or, positive., a) The work done in sliding a load is . . with respect to frictional force., (zero, positive, negative, infinity), b) State and prove the work energy theorem for constant force., c) A pump on the ground floor of a building can pump water to fill a tank of volume, 30 m 3 in 15 minutes. If the tank is 40 m above the ground and the efficiency of the, pump is 30%, how munch electric power is consumed by the pump?, 1, 2, 2, Best wishes to all, HSPTA MALAPPURAM, O HSPTA, MALAPPURM, PHYSOL-The solution for learning Physics, Prepared by Higher Secondary Physics Teachers Association Malappuram