A bus increases its speed from 36 km h to 72 km h in 10 seconds. What is its acceleration?

We know from the question that, Initial velocity of the bus, u = 36 km h = 36 × 5 18 = 10 m s . Final velocity of the bus, v = 72 km h = 72 × 5 18 = 20 m s . Time taken by the bus, t = 10 s . From the definition, We know that acceleration is the rate of change of velocity. ∴ a = v - u t ⇒ a = 20 - 10 10 = 1 m s 2

A scooter acquires a velocity of 36 km h in 5 s just after the start. Calculate the acceleration of the scooter.

We know from the question that, Initial velocity of the scooter, u = 0 Final velocity of the scooter, v = 36 km h = 36 × 5 18 = 10 m s . Time taken by the scooter, t = 5 s . From the definition of acceleration, we know that it is the rate of change of velocity. ∴ a = v - u t ⇒ a = 10 - 0 5 ⇒ a = 2 s

A bus travelling at 30 km h speeds up to 60 km h in 6 seconds. What is its acceleration in m s 2 ?

We know from the question that, Initial velocity of the bus, u = 30 km h = 30 × 5 18 = 50 6 m s Final velocity of the bus, v = 60 km h = 60 × 5 18 = 100 6 m s Time taken by the bus, t = 6 s From the definition, acceleration is the rate of change of velocity. ∴ a = v - u t ⇒ a = 100 6 - 50 6 6 ⇒ a = 50 36 = 1 . 389 m s 2

Describe the motion of a body which is accelerating at a constant rate of 10 m s 2 . If the body starts from rest, how much distance will it cover in 2 s.

We know from the question, Initial velocity of the body, u = 0 Acceleration of the body, a = 10 m s 2 Time taken by the body to cover the distance required, t = 2 s Considering the variables given, we can safely say that this uniformly accelerated motion. This is because the acceleration of the body is constant. To find the distance, we use the second equation of motion. s = u t + 1 2 a t 2 Substituting the values in this equation, we get, ∴ s = 0 × 2 + 0 . 5 × 10 × 4 ⇒ s = 20 m