Class 9 Work and Energy Quiz set 1 1. The number of joules contained in 1 kWh is 36 x 10⁴ 3.6 x 10⁶ 36 x 10² 36 x 10³ 2. The speed of a motor car becomes six times, then the kinetic energy becomes 6 times 36 times 12 times 24 times 3. A stretched string possesses _______ energy. Kinetic elastic potential magnetic electric 4. No work is said to have been done when an object moves’ at an angle of ……….. with the direction of the force. 90° 180° 0° 45° 5. Work done upon a body is always positive always negative a scalar quantity a vector quantity 6. The work done in lifting a mass of 1 kg to a height of 9.8 m is (9.8)² 1 J 9.8 J none of these 7. The K.E. of a body in increased most, by doubling its speed mass weight density 8. Two unequal masses posses the same K.E. Then, the heavier mass has Smaller momentum Greater momentum Greater speed The same momentum as the lighter mass 9. A body of mass 20 kg is dropped from a height of 2m. If ‘g’ is taken to be equal to 10 m/s², the Kinetic energy of the body, just before striking the ground, will be 40 J 4 J 400 J none of these 10. A ball of mass 200 g fall form height of 5 m. what is its K.E. when it just reaches the ground ? 980 J 9.8 J none of these 98 J 11. The mass of an object P is double the mass of Q. If both move with the same velocity, then the ratio of K.E. of P to that of Q is 1 : 2 2 : 1 1 : 4 4 : 1 12. Two unequal masses posses the momentum, then the kinetic energy of the heavier mass is ………… the kinetic energy of the lighter mass. smaller than same as greater than much greater than 13. When the momentum of a body decreases 10%, its K.E. decreases by 40% 20% none of these 36% 14. A body is thrown vertically up from the earh′s surface. What happened to its P.E. during the motion ? decreases remains constant increases first decreases then increases 15. 1 hp is equal to 7.46 kW 0,746 kW 74.6 kW 746 kW Loading … Question 1 of 15

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