Question

A ball of mass 1kg is thrown upward with a speed of 9.9m/s find work done in time 1sec

Answer 1

Answer:

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Answer 2

Answer

Work done by ball = 49 J

Explanation

Given:-

• Mass of ball, m = 1 kg
• Initial velocity of ball with which it is thrown upward, u = 9.9 m/s
• Time, t = 1 sec

To find:-

• Work done, W =?

Formula required:-

• Second equation of kinematics

        s = ut + 1/2 at²

• Formula for work done

       W = F s = m a s

[ Where s is distance covered, u is initial velocity, a is acceleration, t is time, W is work done, F is force and m is mass]

Solution:-

Let us take the distance covered by ball as 's' and acceleration 'a' will be equal to the acceleration due to gravity  'g' = -9.8 m/s² (negative because body is moving upward)

Using second equation of kinematics

→ s = ut + 1/2 at²

→ s = (9.9)(1) + 1/2 (-9.8)(1)²

→ s = 9.9 - 4.9

→ s = 5 m

Now, Using the formula for Work done

→ W = m a s

→ W = (1) (9.8) (5)

→ W = 49 J

     

Therefore,

• Work done by ball is 49 Joules.