Motion

Question 1

State of Rest

Answer 1

An object is said to be in the state of rest if it does not change its position with respect to time and its surroundings.

Question 2

State of Motion

Answer 2

An object is said to be in the state of motion if it changes its position with respect to time and its surroundings.

Question 3

Scalar quantity

Answer 3

Physical quantities having magnitude but no direction are called scalars. e.g., distance, speed.

Question 4

Vector quantity

Answer 4

Physical quantities having both magnitude and direction are called vectors. e.g., displacement, velocity.

Question 5

Difference between Distance & Displacement

Answer 5

(1) Distance is the length of actual path travelled by an object whereas displacement is the shortest length between initial and final position of an object.
(2) Distance is a scalar quantity whereas displacement is a vector quantity.
(3) Distance remains positive, it cant be zero or negative whereas displacement can be positive, negative or zero.
(4) Distance can be equal to displacement or its greater than displacement whereas displacement can be equal to the distance or its lesser than the distance. It can never be greater than displacement in any situation.

Question 6

Speed

Answer 6

The measurement of distance travelled by a body per unit time is called speed.
Speed = Distance travelled / Time taken (v= s/t)
SI Unit: meter/second (m/s)

Question 7

Velocity

Answer 7

It is the speed of a body in given direction.
Velocity = Displacement / Time
Velocity is a vector quantity. Its value changes when either its magnitude or direction changes.
It can be positive (+ve), negative (-ve) or zero.

Question 8

Uniform Motion

Answer 8

When a body travels equal distance in equal interval of time, then the motion is said to be uniform motion.

Question 9

Non-uniform Motion

Answer 9

In this type of motion, the body will travel unequal distances in equal intervals of time.