CBSE IX PHYSICS:
1. Under what conditions work is said to be done?
2. State the energy changes taking place in the following cases: (i) A car moves up a hilly road.(ii) a stone projected vertically upward returns
3. Give few examples where energy is possessed by a body due to its change in shape.
4. When we cut a log of wood with a saw it becomes warm, why?
5. Is it possible that force is acting on a body but still work done is zero? Explain.
6. A rocket of mass 3x106 kg takes off from a launching pad and acquires a vertical velocity of 1 km/s at an altitude of 25 km. calculate (a) the potential energy and (b) the kinetic energy. (g = 9. 8m/s2)
7. If a man lifts a load up with the help of a rope such that it raises the load of mass 50 kg to a height of 20 m in 100 sec. Find the power of man
8. A ball is dropped from a height of 5m. Find the velocity of the ball just before it reaches the ground. Do you require the value of mass to find the velocity?
9. Two persons A and B do same amount of work. The person A does that work in t1 sec and the
person b in t2 sec. Find the ratio of power delivered by them.
10. Why do our hands become warm when rubbed against each other? Explain.
11. The kinetic energy of a body of mass 15 kg is 30J. What is its momentum?
12. Give an example for each of the following energy conversion: (1) electrical energy to kinetic
energy. (2) Chemical energy to electrical energy (3) sound energy to electrical energy
13. Two bodies have same momentum. Which will have greater kinetic energy- heavier body or lighter
body?
14. An electric bulb of 60w is used for 6h per day .Calculate the units of energy consumed in one day
by the bulb.
15. A boy of mass 50kg runs up to a stair case of 45 steps in 9s. If the height of a step is 15cm, find
his power. (g= 10m/s2)
16. Two particles of masses 1g and 2g have equal momentum. Find the ratio between their kinetic energies?
17. What will be the work done by the string, when a stone is tied to a string and whirled in a circle?
18. A locomotive exerts a force of 7500N and pulls a train through 1.5 km. How much work is done
by locomotive?
19. What work a boy of mass 50kg will do in order to increase running speed from 9km/h to 18km/h.
20. The speed of a moving body is halved. What is the change in its K.E.?
Solved CBSE Test papers:
Class 9 Work, Energy ,Power_ Solved Questions - 01
Class 9 Work, Energy ,Power_ Solved Questions - 02
Class 9 Work, Energy ,Power_ Solved Questions - 03
Class 9 Work, Energy ,Power_ Solved Questions - 04
Class 9 Work, Energy ,Power_ Solved Questions - 05
Class 9 Work, Energy ,Power_ Solved Questions - 06
Class 9 Work, Energy ,Power_ Solved Questions - 02
Class 9 Work, Energy ,Power_ Solved Questions - 03
Class 9 Work, Energy ,Power_ Solved Questions - 04
Class 9 Work, Energy ,Power_ Solved Questions - 05
Class 9 Work, Energy ,Power_ Solved Questions - 06
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