September 21, 2021

# Class 9 Science Chapter 9 mcq – 1

Class 9 – Science

Chapter – 9 Force and Motion

Quiz -1  (1 Mark Questions)

1. (1) Newton’s law of motion is also known as –
2. (a) Law of Momentum                               (b) Law of Inertia
3. (c) Law of action & Reaction (d) None of these
4. Ans  (b) Law of Inertia

(2) The inability of the body to change its state of rest or motion is  –

• (a) Momentum (b) Acceleration
• (c) Inertia (d) None of these
• Ans  (c) Inertia

(3)  The people in the bus are pushed backwards when the bus starts suddenly due to –

• (a) Inertia due to motion (b) Inertia due to direction
• (c) Inertia due to rest (d)None of these
• Ans (c) Inertia due to rest
• (4) S.I unit of Force is  –

(a)   Pascal  (b)Newton

(c) Newton – meter (d)None of these

Ans (b) Newton

(5) Which has a more Inertia ?

(a)    5 kg stone (b)    A football

(c)    A wooden stick                (d)    None of these

Ans (a) 5 kg stone

(6) Which is not a force –

(a)  Pushing a wall (b)  Pushing a bag

(c)  Pushing a heavy stone (d)  None of these

Ans (a) Pushing a wall

(7)  Which is a force?

• (a)  Two same weight people are pushing a heavy stone opposite to each other.
• (b)Two same weight people are pushing a wall.
• (c) Two different weight people are pushing a heavy stone opposite to each other.
• (d)None of  these
• Ans (c) Two different weight people are pushing a heavy stone opposite to each other.

(8)   An unbalanced force is –

(a)  Two same weight people are pushing a heavy stone opposite to each other.

(b)  Two different weight people are pushing a wall.

(c)  Two different weight people are pushing a heavy stone opposite to each other.

(d)   None of these

Ans – (c) Two different weight people are pushing a heavy stone opposite to each other.

(9) The Inertia of an object tends to cause the object –                                                                        (a) To increase its speed  (b) to decrease its speed

(c) To resist any change in its state of motion (d) to decelerate due to friction

Ans (c) to resist any change in its state of motion

(10)  Formula of Force ?

(a)  F = ma                                                 (b)  F = mv

(c)  F = ua                                                   (d)   None of these

Ans (a) F = ma

(11) Name the scientist who proved for the first time that objects move with constant speed when no force acts on them –

• (a) Galileo                               (b) Newton
• (c) Einstein (d) None of these
• Ans  (a) Galileo

(12) Which of them would have highest inertia?   –

• (a) Aluminium (b) Steel
• (c) Wood (d) None of these
• Ans (b) Steel

(13)  Which object has less inertia –

• (a) 5 kg Iron bar (b) 5 kg Cotton
• (c) 5 kg  steel (d) None of these
• Ans (b) 5 kg Cotton
• (14) Why passengers fall in the forward when bus driver applies sudden brakes?

(a) Due to acceleration

•   Due to Impulse
•   Due to Inertia
•     None of these

Ans (c) Due to Inertia

• The seat belts are provided in the cars so that if the car stops suddenly due to an emergency braking, the persons sitting on the front seats are not thrown forward violently and saved from getting injured. Can you guess the law due to which a person falls in forward direction on the sudden stopping of the car?

(a)    Newton’s first law of Motion

(b)    Newton’s second law of Motion

(c)    Newton’s Third law of Motion

(d)   Newton’s law of Gravitation

Ans (a) Newton’s first law of Motion

• Newton’s first law of motion says that a moving body should continue to move forever, unless some external forces act on it. But a moving cycle comes to rest after some time if we stop pedaling it. Can you choose the correct reason for the stoppage of cycle?

(a)  Frictional Force

(b)  Gravitational Pull of the earth

(c)  Heat of the environment

(d)  None of these

Ans (a) Frictional Force

7.  The Inertia of an object depends on?

•  Mass of the object
•  Momentum of  the object
•  Shape of the object
•  Speed of the object

Ans (a) Mass of the Object

8.   An unbalanced force is –

(a)  Hitting a ball

(b)  shedding leaf from the plant

(c)  Gravitation

(d)   all of these

Ans – (d) All of these

9. Force is a quantity –

(a) Vector quantity   (b) Scalar quantity

(c) It is not a quantity

(d) None of these

Ans (a) Vector quantity

10.  Which is a vector quantity ?

(a) Mass

(b)  Speed                                                                                                                                                                                           (c) Acceleration                                                                                                        (d)   None of these

Ans (c) Acceleration 