Question

A car accelerates uniformly from 18km/hr to 36km/hr in 5sec. Calculate
(i) the acceleration and
(ii) the distance covered by the car in that time.​

Answer 1

The acceleration of the car is 1ms^-2

The distance covered by the car in that time is 37.5 m

Explanation:

we know that the 1st equation of motion

v=u+at

we have(converting hr into m/s)

u=18 km/hr= 18*1000/60*60= 5 m/s

v=36 km/hr=36*1000/60*60=10 m/s

t=5 sec

Now lets formulate

v=u+at

10=5+5 a

5=5 a

a=1 m/s

Now lets find the distance covered by the car in time

Lets use 3rd equation of motion,

 v^2 - u^2 = 2 as

 (10)^2 - (5)^2 = 2 × 1 × s

 100 - 25 = 2 s

 75 = 2 s

 75/2 = s

s = 37.5 m.

Thus the distance covered by car is 37.5 m.