CBSE Class 9 - CH 11 - Work and Energy (Worksheet)
Work and Energy
1. A force acting on a body shows a displacement in the direction normal to the direction of the force. It is said _______ done on the body.
2. A force acting on a body shows a displacement in the direction of the force. It is said _______ is done on the body.
3. Work done is defined as the product of _____ and ______ in the direction of force.
4. SI Unit of work is _______.
5. 1 Joule = ____ × ____.
6. Work done on an object is _____ if displacement is zero.
7. Work is a ______ (scalar/vector) quantity.
8. Work done is positive when the angle between force and displacement is ____ (acute/obtuse)
9. Work done is negative when the angle between force and displacement is ____ (acute/obtuse)
10. An object moving in a circular orbit. The work done by the centrepetal force acting on the object is ______ (zero/non-zero).
11. Work done against a force is stored as _____.
12. Ability to do work is called _______.
13. Ability of a body to do work due to its position or configuration is known as _________ of the body.
14. A form of energy an object has because of its motion is called ________.
15. A stretched rubber band acquires _________(potential/kinetic) energy.
16. Work done against gravity in lifting a mass is stored as ______. Numerically, it is
equal to m ×_ ×__.
17. Work done by gravity on a falling body is available as ______ (kinetic/potential) energy on reaching the ground.
18. Kinetic Energy = ½ × _ × _
19. If the mass is doubled while its speed remains the same, the kinetic energy will be _____ (be same/double/four times) of the initial kinetic energy.
20. The sum of P.E. and K.E. is called __________.
Answer:
1. work is not
2. work
3. force and displacement
4. Joules
5. 1 Newton × 1metre
6. zero
7. scalar
8. acute
9. obtuse
10. zero.
11. energy
12. energy
13. potential energy
14. kinetic energy
15. potential energy
16. potential energy, m×g×h
17. kinetic
18. ½ m v2
19. double
20. mechanical energy
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