Question

state the reasons if it is possible or not for any object in motion to have:
a)zero distance covered and may have non zero displacement
b)zero speed and may have non zero velocity
c)zero speed at an instant but non zero acceleration at the same time
d)positive acceleration while speeding up

Answer 1

(a) Impossible, (b) Possible,

 Reason : When an object is thrown upward, at the highest point its velocity becomes zero for a slice of time, but its acceleration (g) remains due to attraction of gravity.

 (c) Impossible

 (d) Possible

Reason : When a moving car applies the break its velocity decreases. The acceleration is against the direction of motion of the car. 

(e) Possible

Reason : Acceleration has a negative value only when velocity and displacement are in opposite direction and acceleration has a positive value only when velocity and displacement are in same direction. 

Or,

(a) Impossible, reason 

(b) Possible, reason

(c) Impossible, reason 

(d) Possible, reason 

(e) Possible, reason