Question

A car accelerates from rest to a speed of 36 km/h in 20 seconds. What is the acceleration of the car in m/s 2 ?

Answer 1

u=0m/s(body starts from rest)

36km/h
$36 \times \frac{5}{18} = 2 \times 5 = 10$
v=10m/s
t=20seconds
$a = \frac{v - u}{t} \\ = \frac{10 - 0}{20} \\ = \frac{10}{20} \\ = 0.5$
So, acceleration is 0.5m/s^2

Answer 2

The acceleration of the car is 0.5 m/s².

Given : The car accelerates from rest to a speed of 36 km/h in 20 seconds.

To find : The acceleration of the car.

Solution :

We can simply solve this numerical problem by using the following process. (our goal is to calculate the acceleration of the car)

Here,

• Initial velocity (u) = 0 m/s (as starts from rest)
• Final velocity (v) = 36 km/h
• Time (t) = 20 seconds

We have to convert the unit of the final velocity in m/s unit.

In case of final velocity,

The car travels in 1 hour = 36 km

Or,

The car travels in 3600 seconds = 36000 m

(As, 1 hour = 3600 seconds ; 1 km = 1000 m)

The car travels in 1 second = 36000/3600 = 10m

So,

The final velocity of the car (v) = 10 m/s

Now,

Acceleration = (v-u)/t

By putting the given values, we get :

Acceleration of the car = (10-0)/20

Acceleration of the car = 0.5 m/s²

(This will be considered as the final result.)

Hence, the acceleration of the car is 0.5 m/s²