Question

A car is moving at a rate of 72km/hrs. How far does the car move when it stops after 4 seconds ?

Answer 1

Answer:

40 meter is the correct answer

Explanation:

hope the answer will help you

Answer 2

Answer:

Explanation:

Given :-

Initial velocity, u = 72 km/h = 72 × 5/18 = 20 m/s

Final velocity, v = 0 (As car stops)

Time taken, t = 4 seconds

To Find :-

Distance covered, s = ??

Formula to be used :-

1st equation of motion, i.e v = u + at

2nd equation of motion, i.e s = ut + 1/2 at²

Solution :-

Putting all the values, we get

v = u + at

⇒ 0 = 20 + a × 4

⇒ a = - 5 m/s

Now, distance covered, s

s = ut + 1/2 at²

⇒ s = 20 × 4 + 1/2 × (- 5) × 4²

⇒ s = 80 + 1/2 × (- 5) × 16

⇒ s = 80 + (- 5) × 8

⇒ s = 80 - 40

⇒ s = 40 m.

Hence, the distance covered by car is 40 m.