Question

From the following statement identify the type of acceleration. A vehicle moving with the velocity of 25 m/s stops after 5 second.

Answer 1

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)

Explanation:

Initial velocity will be 25 m/s because the vehicle starts with speed 25 m/s. Note :- Negative sign will show that the acceleration decreased that means it is negative acceleration . ∴ Hence , the acceleration is negative type .