Question

A car accelerates uniformly from 18 kmph to 72 kmph in 5 s. The acceleration of the car (in m/sq.s) is:
A) 3 B) 5 C) 6 D) 7

Answer 1

Answer:

plz refer the above attachment

Answer 2

A car accelerates uniformly from 18 kmph to 72 kmph in 5 s.

We have to find the acceleration of the car.

From above data we have; initial velocity of the car is 18 km/hr, final velocity is 72 km/hr and time is 5 sec.

Firstly convert km/hr into m/s. To do this, multiply the given value by 5/18.

⇒ u = 18×5/18 = 5 m/s and v = 72×5/18 = 20 m/s

Using the First Equation Of Motion:

v = u + at

Substitute the known values in the above formula,

→ 20 = 5 + a(5)

→ 20 - 5 = 5a

→ 15 = 5a

Divide by 5 on both sides,

→ 15/5 = 5a/5

→ 3 = a

Therefore, the acceleration of the car is 3 m/s².

Option A) 3 [ Answer ]