Question

A body moving with uniform acceleration travels 84 m is the first 6s and 180 m in the next 5s.
Find :
(i) the initial velocity
(ii) the acceleration of the body

Answer 1

(i) the initial velocity = 4 ms-1

(ii) the acceleration of the body = 2 ms-2

Explanation:

Given that a body travels 84 m in first 6 seconds and 180 m in the next 5 seconds.

Let's assume acceleration is a and initial velocity is u.

We know that s = ut + 1/at^2

84 = 6u +18a for the first phase of movement -------- (1)

Final velocity at the end of 6 seconds will be u + 6a

For the second phase of movement, we get

180 = (u+6a)5 + 1/2*a*25

5u + (85/2)a = 180 -------------------------(2)

By solving the two equations, we get a = 2 ms-2 and u = 4 ms-1