Laws of Motion MCQs: Test Your Knowledge | Science Study Material

Laws of Motion | Science

I. Choose the correct answer

1) Inertia of a body depends on

a)

weight of the object

b)

acceleration due to gravity of the planet

c)

mass of the object

d)

Both a & b

2) Impulse is equals to

a)

rate of change of momentum

b)

rate of force and time

c)

change of momentum

d)

rate of change of mass

3) Newton’s III law is applicable

a)

for a body is at rest

b)

for a body in motion

c)

both a & b

d)

only for bodies with equal masses

4) Plotting a graph for momentum on the X-axis and time on Y-axis. slope of momentum-time graph gives

a)

Impulsive force

b)

Acceleration

c)

Force

d)

Rate of force

5) In which of the following sport the turning of effect of force used

a)

swimming

b)

tennis

c)

cycling

d)

hockey

6) The unit of ‘g’ is m s^-2. It can be also expressed as

a)

cm s^-1

b)

N kg^-1

c)

N m² kg^-1

d)

cm² s^-2

7) One kilogram force equals to

a)

9.8 dyne

b)

9.8 × 10⁴ N

c)

98 × 10⁴ dyne

d)

980 dyne

8) The mass of a body is measured on planet Earth as M kg. When it is taken to a planet of radius half that of the Earth then its value will be____kg

a)

4 M

b)

2M

c)

M/4

d)

M

9) If the Earth shrinks to 50% of its real radius its mass remaining the same, the weight of a body on the Earth will

a)

decrease by 50%

b)

increase by 50%

c)

decrease by 25%

d)

increase by 300%

10) To project the rockets which of the following principle(s) is /(are) required?

a)

Newton’s third law of motion

b)

Newton’s law of gravitation

c)

law of conservation of linear momentum

d)

both a and c

II. Fill in the blanks

1. To produce a displacement force is required.

2. Passengers lean forward when sudden brake is applied in a moving vehicle. This can be explained by inertia of motion.

3. By convention, the clockwise moments are taken as negative and the anticlockwise moments are taken as positive.

4. Gear is used to change the speed of car.

5. A man of mass 100 kg has a weight of 980 N at the surface of the Earth.

Key Points to Remember: Laws of Motion | Chapter 1 | 10th Science

Points to Remember: Laws of Motion

Science | Chapter 1

• Mechanics is divided into statics and dynamics.
• Ability of a body to maintain its state of rest or motion is called Inertia.
• Moment of the couple is measured by the product of any one of the forces and the perpendicular distance between two forces.
• SI unit of force is newton (N). C.G.S unit is dyne.
• When a force F acts on a body for a period of time t, then the product of force and time is known as ‘impulse’.
• The unit of weight is newton or kg f
• The weight of a body is more at the poles than at the equatorial region.
• Mass of a body is defined as the quantity of matter contained in the object. Its SI unit is kilogram (kg).
• Apparent weight is the weight of the body acquired due to the action of gravity and other external forces on the body.
• Whenever a body or a person falls freely under the action of Earth’s gravitational force alone, it appears to have zero weight. This state is referred to as ‘weightlessness’.

Inertia: Understanding Types and Examples | 10th Science, Chapter 1: Laws of Motion

Introduction 10th Science Chapter 1: Laws of Motion

Inertia - Types and Examples of Inertia

INERTIA

While you are travelling in a bus or in a car, when a sudden brake is applied, the upper part of your body leans in the forward direction. Similarly, when the vehicle suddenly is move forward from rest, you lean backward. This is due to, any body would like to continue to be in its state of rest or the state of motion. This is known as ‘inertia’.

The inherent property of a body to resist any change in its state of rest or the state of uniform motion, unless it is influenced upon by an external unbalanced force, is known as ‘inertia’.

In activity described above, the inertia of the coin keeps it in the state of rest when the cardboard moves. Then, when the cardboard has moved, the coin falls into the tumbler due to gravity. This happen due to ‘inertia of rest’.

1. Types of Inertia

a) Inertia of rest: The resistance of a body to change its state of rest is called inertia of rest.

b) Inertia of motion: The resistance of a body to change its state of motion is called inertia of motion.

c) Inertia of direction: The resistance of a body to change its direction of motion is called inertia of direction.

2. Examples of Inertia

• An athlete runs some distance before jumping. Because, this will help him jump longer and higher. (Inertia of motion)
• When you make a sharp turn while driving a car, you tend to lean sideways, (Inertia of direction).
• When you vigorously shake the branches of a tree, some of the leaves and fruits are detached and they fall down, (Inertia of rest).