Test: Rest And Motion - Class 9 MCQ

In this case
Displacement = hypotenuse
Displacement = (8² +6²)^1/2 = 10 m

"Displacement will be zero because displacement is the difference between initial and final position but after one revolution the second hand came to its initial position; so it's final and initial position is same so displacement is zero "

His displacement will be zero although distance covered is non-zero since he ends up where he started.

Displacement can be zero but distance cannot be zero because distance is the total path covered but displacement is the shortest distance between the initial and final position. It can be zero at the end of one round.

60km.east + 90km.west =150km.

Non Uniform motion is defined as the motion of an object in which the object travels with varied speed and it does not cover same distance in equal time intervals, irrespective of the time interval length.

Examples:

1. If a car covers 10 meters in first two seconds, and 15 meters in next two seconds.

2. The motion of a train.

Topic in NCERT: Non-Uniform Motion

Line in NCERT: "we come across motions where objects cover unequal distances in equal intervals of time, for example, when a car is moving on a crowded street or a person is jogging in a park. These are some instances of non-uniform motion."

Vector quantity has both magnitude and direction but scalar quantity have only magnitude

Topic in NCERT: SPEED WITH DIRECTION

Line in NCERT: "The quantity that specifies both these aspects is called velocity."

Answer: (b) displacement

Explanation: Velocity is defined as displacement per unit time.

A body whose position with respect to surrounding doesn't change is said to be in a state of rest .

Topic in NCERT: MOTION

Line in NCERT: "In everyday life, we see some objects at rest and others in motion."

Answer: (a) equal

Explanation: A body moving in a straight line has a uniform motion if it travels an equal distance in equal time intervals.

Answer: (c) The boy is moving with accelerated motion as the boy undergoes acceleration when moving with a uniform velocity on a merry-go-round ride.