Question

At the start of a race, a runner’s velocity changes from 0 to 4.0 m/s. It takes him 2 seconds to speed up. His acceleration is blank m/s2.

Answer 1

Explanation:

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Answer 2

Given:-

• Initial velocity ,u = 0m/s

• Final velocity ,v = 4m/s

• Time taken,t = 2s

To Find:-

• Acceleration of the runner,a

Solution:-

By using 1st equation of motion

• v = u+at

Substitute the value we get

→ 4 = 0 +a×2

→ 4-0 = a×2

→ a = 4/2

→ a = 2m/s²

∴ The acceleration of the runner is 2m/s².

Additional Information !!

• The rate of change of velocity at per unit time is called acceleration .

• SI unit of acceleration is m/s²

• It is vector Quantity ( both magnitude and direction).

• Negative acceleration is called retardation.