# Ch – 9 Force & Laws Of Motion

Q.1: In 1581, Galileo wrote his first scientific book ________________, where he described Archimedes’ method of finding the relative densities of substances using a balance.

a) Letters on the Sunspots

b) Starry Messenger

c) The Little Balance

Q.2: The SI unit of momentum is ____________________.

a) metre per second

b) kilogram-metre per second

c) None

Q.3: A force of one Newton produces an acceleration of _________ on an object of mass 1 kg.

a) 1 m s -1

b) 1 m s

c) (-1) m s -1

Q.4: ___________ is the natural tendency of an object to resist a change in its state of motion or of rest.

a) inertia

b) force

c) momentum

Q.5: To accelerate the motion of an object, a/an _____________ force is required.

a) balanced

b) unbalanced

c) both

Q.6: The ___________ law of motion gives us a method to measure the force acting on an object as a product of its mass and acceleration.

a) first

b) second

c) third

Q.7: Frictional forces act opposite to the direction of motion.

a) True

b) False

Q.8: Which law of motion is also known as the “law of inertia” ?

a) first

b) second

c) third

Q.9: The _________ of an object is a measure of its inertia.

a) acceleration

b) force

c) mass

Q.10: Which of the following statements are correct regarding the “Conservation Laws” ?

i) A conservation law can not be proved.

ii) A single experiment against the law can not disprove it.

iii) It can be verified by conducting experiments.

a) i and ii

b) ii and iii

c) i and iii

1. c
2. b
3. a
4. a
5. b
6. b
7. a
8. a
9. c
10. c

1. Love Alone says: