How is the speed related to the magnitude of velocity?
A.
Greater
B.
Lesser
C.
Equal
D.
None of Above
Answer: Option A
Explanation:
Due to change in direction of motion, the length of the path traversed by a body is generally greater than the magnitude of its displacement. So the speed is greater than the magnitude of the velocity.
Two balls of different masses (one lighter and one heavier) are thrown vertically upward with same initial speed. Which one will rise to a greater height?
A.
The lighter one
B.
The heavier one
C.
Neither
D.
Both the balls
Answer: Option D
Explanation:
Both he balls will rise to the same height. It is because, for a body moving with given initial velocity and acceleration, the distance covered by the body does not depend on the mass of the body.
For a particle in one dimensional motion, which of the following is true?
A.
Positive value of acceleration must be speeding up
B.
Constant speed must have zero acceleration
C.
Zero speed may have non-zero velocity
D.
Zero speed at any instant may have zero acceleration at the instant
Answer: Option B
Explanation:
When a particle moves with a constant speed in the same direction, neither the magnitude nor the direction of velocity changes and so acceleration is zero. In case a particle rebounds instantly with the same speed, its acceleration will be infinite which is physically not possible.
