Ncert – class 9- science – Chapter 10 – Work and Energy 1 Welcome to your Ncert - class 9- science - Chapter 10 – Work and Energy 1 1. A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to $$ t^{2} $$ $$ t^{3/ 4} $$ $$ t^{3/ 2} $$ $$ t^{1 / 2} $$ None 2. The height of the water dam in the hydroelectric power station is 20 m. How much water. in 1 second, should fall on turbine, so that 1 MW power is generated ?(g=10m/s^2 ) 500kg 7,500kg 5000kg 10000kg None 3. A ball of mass 2 kg hits a floor with a speed of 4 m/s at an angle of 60ºwith the normal. If (e=1/2); then the change in the kinetic energy of the ball is -9J -6J -12J -3J None 4. Whenever energy gets transformed, the total energy_______. Varies with time Varies with position None of these Remains unchanged None 5. We can explain free-fall of an object on the basis of? Conservation of Kinetic energy Conservation of energy Conservation of potential energy Work-energy theorem None 6. A constant force of 5N is applied on a block of mass 20 kg for a distance of 2.0 m, the kinetic energy acquired by the block is 15 J 10 J 20 J 50 J None 7. A body is falling a height ℎ. After it has fallen a height ℎ/2. it will possess only kinetic energy more kinetic and less potential energy half potential energy and half kinetic energy only potential energy None 8. A ball is allowed to fall from a height of 10m. if there is 40% loss of energy due is impact then after one impact ball will go up to 4m 10m 8m 6m None 9. If water is flowing in a pipe at a height 4m from the ground then its potentialenergy per unit volume is (Reference is taken at ground, g=10m/s 2) $$ 30 \mathrm{kJ} / \mathrm{m}^{3} $$ $$ 20 \mathrm{kJ} / \mathrm{m}^{3} $$ $$ 10 \mathrm{kJ} / \mathrm{m}^{3} $$ $$ 40 \mathrm{kJ} / \mathrm{m}^{3} $$ None 10. A ball rolling on the ground possesses heat energy potential energy kinetic energy no energy None 11. Bullet 2 has twice the mass of bullet 1. Both are fired so that they have the same speed. If the kinetic energy of bullet 1 is K, is the kinetic energy of bullet 2 2K 0.25K 0.71K 0.5K None 12. From an automatic gun a man fires 360 bullets per minute with a speed of 360 km/hr. If each bullet weighs 20g, the power of the gun is 600 W 300 W 150 W 75 W None 13. At the start of the free-fall of an object from height ℎ, the potential energy is _____ and kinetic energy is _____. Infinite, mgh mgh, infinite Zero mgh mgh, zero None 14. 9800 joule of energy was spent to raise a mass of 50kg, the mass was raised to a height of 10m 980m 20m none of these None 15. Work done is equal to? None of these Acceleration Change in kinetic energy Kinetic energy None 16. When a body falls freely towards the earth, then its total energy: Decreases Increases Remains constant First increases and then decreases None 17. The spring will have maximum potential energy when both (a) and (b) it is pulled out neither (a) nor (b) it is compressed None 18. If a body is released from a certain height, during its fall. Its kinetic energy increases and potential energy decreases Its potential energy increases and kinetic energy decreases. Both potential and kinetic energy of the body decrease Both potential and kinetic energy of that body increase None 19. Is the work required to be done by an external force on an object on a frictionless, horizontal surface to accelerate it from a speed v to a speed 2v. twice the work required to accelerate the object from v=0 to v three times the work required to accelerate the object from v=0 to v, four times the work required to accelerate the object from 0 to v equal to the work required to accelerate the object from v=0 to v, None 20. When the force and the displacement are in the opposite directions, the work done by the force is .......... zero notformthis negative positive None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
