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 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 20 J 10 J 50 J 15 J None 2. A ball rolling on the ground possesses heat energy kinetic energy no energy potential energy 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 -3J -12J -6J -9J None 4. The spring will have maximum potential energy when both (a) and (b) it is compressed neither (a) nor (b) it is pulled out None 5. 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 ) 7,500kg 5000kg 500kg 10000kg None 6. Whenever energy gets transformed, the total energy_______. Varies with time Varies with position Remains unchanged None of these None 7. At the start of the free-fall of an object from height ℎ, the potential energy is _____ and kinetic energy is _____. mgh, infinite Zero mgh mgh, zero Infinite, mgh 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 6m 4m 10m 8m None 9. 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 150 W 75 W 600 W 300 W None 10. 9800 joule of energy was spent to raise a mass of 50kg, the mass was raised to a height of none of these 10m 20m 980m None 11. If a body is released from a certain height, during its fall. Both potential and kinetic energy of that body increase 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 None 12. 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 $$ t^{2} $$ $$ t^{1 / 2} $$ $$ t^{3/ 4} $$ $$ t^{3/ 2} $$ None 13. 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 14. 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 only potential energy half potential energy and half kinetic energy None 15. When the force and the displacement are in the opposite directions, the work done by the force is .......... zero notformthis positive negative None 16. Work done is equal to? Kinetic energy None of these Change in kinetic energy Acceleration None 17. 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 0.5K 0.71K None 18. When a body falls freely towards the earth, then its total energy: Remains constant First increases and then decreases Decreases Increases 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. three times the work required to accelerate the object from v=0 to v, twice the work required to accelerate the object from v=0 to v equal to 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 None 20. 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 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.
