Question

Brakes are applied to a car traveling at 30m/ sec. Its velocity is reduced to 20m/sec in 5 sec. Calculate the distance covered by it. *​

Answer 1

Given:-

• Initial velocity (u) = 30m/s

• Final velocity (v) = 20m/s

• Time taken (t) = 5s

To Find:-

• Distance covered by the car

Solution:-

By using 1st equation of motion we get

→ v = u+at

Substitute the value we get

→ 20 = 30 + a×5

→ 20-30 = a×5

→ -10 = a×5

→ a = -10/5

→ a = -2m/s

here negative sign show retardation

Now Calculating distance

By using 3rd equation of motion we get

→ v² = u² +2as

Substitute the value we get

→ 20² = 30² + 2×(-2) ×s

→ 400 = 900 -4×s

→ 400-900 = -4×s

→ -500 = -4×s

→ s = -500/-4

→ s = 500/4

→ s = 125 m

∴ The Distance covered by the car is 125metre