Question

A car starts from rest and accelerates at a constant rate traveling a distance of 147 m in sec. The car continues to accelerate at the same rate for an additional 158 m. If the speed of the car after it has travelled the (147+158) m is 93 m/s, how long (in secs) did the car accelerate for?

Answer 1

From Newtons law

V² - U² = 2as where v is the final velocity of the body, u is the initial velocity of the body, a is the acceleration and s is the total distance covered by the body.

Here V = 93m/s

U =0, s = 305 m

Therefore acceleration

a = V² /2s = 8649/610

a = 14.18 m/s²

Now wr know that V = U + at , where t is the time travelled by the body.

Here U = 0 so

t = V/a = 93/14.18 = 6.56 s

Time taken by the body to cover 305 m with constant acceleration is

t = 6.56 s