Question

21. A particle at time t = 0 started with initial velocity
of 8 m/s from a point and moves with a constant
acceleration of 2 m/s2 opposite to velocity. Find
the average speed of the particle between the time
interval t = 3 sec to t = 6 sec
(a) 1 m/s
(b) 1/3 m/s
(c) 4/3 m/s
(d) 5/3 m/s​

Answer 1

Answer:

Explanation:

velocity = u+at

velocity = 8-2t

velocity becomes zero when it comes to zero

velocity becomes zero at t=4 sec

lets apply distance covered in 3 to 4 sec

s=ut+1/2at^2

s=8(3) - 1/2(2)(9)

s=15 m

s=ut+1/2at^2

s=4(8)-1/2(2)(16)

s=16m

distance covered in 3 to 4 sec = 1m

distance covered in 6 sec  = 6(8)-1/2(2)(36) = 12 m

distance covered in 4 to 6 sec = 4m

average speed = distance / time = 5/3 m/s