Question

A car travelling at 60 mph slams on the brakes to avoid hitting a deer. The car comes to a safe stop 6 sec after applying the brakes. What is the car’s acceleration?

Answer 1

Given:-

• Initial velocity,u = 60mph

• Final velocity ,v = 0m/s

• Time taken ,t = 6s

To Find:-

• Acceleration of the car ,a

Solution:-

Firstly we convert the speed of car into m/s

So,

→ 1600 ×60/3600 = 27m/s

Now we know that acceleration is defined as the rate of change of velocity at per unit time.

• a = v-u/t

Substitute the value we get

→ a = 0-27/6

→ a = -27/6

→ a = -4.5m/s²

here, negative sign show retardation

Therefore, the acceleration of the car is 4.5m/s²

Additional Information!!

Some equation of motion are

• v = u +at

• s = ut +1/2at².

• v² = u² + 2as

Here,

v is the final velocity

u is the initial velocity

a is the acceleration

s is the displacement or Distance

t is the time taken