Question

A ball rolls down an inclined track 2m long in 4s. Find (1) acceleration (2) time taken to cover the second meter of the track and (3) speed of the ball at the bottom of the track .

Answer 1

Answer & Explanation:

Given,

Initial Velocity (u) = 0 m/s

Distance (S) = 2m

Time (t) = 4s

1. Acceleration (a) = S = ut+0.5at²

= 2 = 0.5a*16

= 2 = 8a

= 0.25 m/s² = a

2. Time taken to cover 2m = 4s

Time taken to cover 1m = (4/2) s

= 2s

3. u = 0 m/s

a = 0.25 m/s²

S = 2 m

t = 4 s

Final Velocity (v) = u+2aS

= 2*0.25*2

= 1 m/s

However, the final velocity will be 0 m/s when the ball will come to rest.

Hope this helps.

Answer 2

Answer:

Explanation:

Distance=2m

Time=4sec

Initial velocity (u)=O

(1) to find acceleration

S=ut+1/2at^2

2=0*4+1/2*a*4^2

2=0+1/2*a*16

2=0+8a

2=8a

a=0.25m/s^2

(2)to find time taken to cover the second meter of the track ..

=Time taken to cover first one meter of the track is given by

S=ut+1/2at^2

1=0+1/2*0.25*t^2

t^2=8

t=2√2

t=2*1.414

t=2.828

t=2.83s

Hence time taken to cover the second meter=4-2.83 =1.17s

(3)speed of the ball at the bottom of the track

v=u+at

v=0+0.25*4

v=1m/s