Question

A car accelerates uniformly from 18 km/hr to 36 km/hr in 5 seconds. Calculate the acceleration.

(a) 1 ms-2

(b) 3.6 ms-2

(c) 2 ms-2

(d) 2.6 ms-2​

Answer 1

Given,

u=18km/h = 18 × 1000 ÷ 60 × 60 = 5m/s

V=36km/hr = 36 × 1000 ÷ 60 × 60 = 10m/s

t= 5 sec

acceleration, a=?

1st equation of motion,

v=u+at

10=5+5a

5a=5

a= 5 ÷ 5 = 1m/s

therefore the correct option is 1ms-2

Answer 2

Answer:

(a) 1 ms-2

Explanation:

acceleration = (Final Speed - Initial Speed)/time

Convert 36 km/hr to m/sec

36 km/hr x 1000m / 3600 sec = 10 m/sec

18 km/hr x 1000 / 3600 sec = 5 m/sec

a = (10 m/sec - 5 m'sec)/5 sec

a = 5m/sec / 5 sec

a = 1 ms-2