Question

Find the initial velocity of a car which is stopped in 10 sec by applying

brakes. Retardation due to brake is 2.5m/s2

Answer 1

initial velocity=?
final velocity=0
time=10
accelaration=-2.5m/s2


a=v-u/t
-2.5=0-u/10
-2.5=-u/10
-2.5*10=-u
-25=-u
25=u

it will help u

Answer 2

Initial velocity of a car is 25 m/s.

According to the given data, a car is stopped by brake application, which comes to rest after 10 seconds of movement. The equation of motion is to be calculated.

The first equation of motion is v = u + at. Here, acceleration is the retardation produced after brake application and the final velocity is zero as the car comes to rest.

$\Rightarrow v=u+a t$

$\Rightarrow 0=u+(-2.5) \times 10$

$\Rightarrow u=2.5 \times 10$

$\bold{\Rightarrow u=25\ \mathrm{m} / \mathrm{s}.}$