Question

A vehicle moving with the velocity of 25 m/s stops after 5 second.

Answer 1

Answer:

Let’s review the 4 basic kinematic equations of motion for constant acceleration (this is a lesson – suggest you commit these to memory):

s = ut + ½at^2 …. (1)

v^2 = u^2 + 2as …. (2)

v = u + at …. (3)

s = (u + v)t/2 …. (4)

where s is distance, u is initial velocity, v is final velocity, a is acceleration and t is time.

In this case, we know u = 25m/s, v = 0, t = 5s and we want to find acceleration, a, so we use equation (3)

v = u + at

0 = 25 + 5a

a = -25/5 = -5m/s^2

So the acceleration is -5m/s^2 (negative meaning retardation)