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