Question

a car starts from rest and moves with constant acceleration of 4m/s for 30 sec.Then the brakes are applied and the car comes to rest in another 60 sec.find magnitude of reterdation

Answer 1

Answer:

thoda roughly krdia.. So, try to understand..

Answer 2

Given:

Initial velocity, u = 0  (car is at rest initially)

Acceleration of the car, a = 4 m/s²

Time of acceleration, t₁ = 30 s

Time of deceleration, t₂ = 60 s

To Find:

The magnitude of retardation of the car.

Calculation:

- Velocity attained by car in 30 seconds:

v = u + at₁

⇒ v = 0 + 4 × 30

⇒ v = 120 m/s

- For retardation (a'):

- Initial velocity of car = v = 120 m/s

- Final velocity of car, v' = 0

⇒ v' = v + a' × t₂

⇒ 0 = 120 + a' × 60

⇒ a' = - 2 m/s²

- So, the magnitude of retardation of the car is -2 m/s².