Question

Certain force acting on a 20 kg mass changes its velocity from 5 m/s to 2 m/s.. calculate the work done by the force​

Answer 1

Answer:

The work done by the force is –210 Joule.

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Explanation:

Given:

• Mass (m) = 20 kg.
• Initial velocity (u) = 5 m/s.
• Final velocity (v) = 2 m/s.

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To find:

We have to find the work done by the force.

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Solution:

We know that,

Work done = Force × distance

⇒ W = F × s

[Since F = ma and s = (v²– u²/2a)]

⇒W = ma{v²– u²/2a}

= 20*a*{(2²– 5²/2a)}

= 20{(4-25/2)}

= 10 × –21 = –210 Joule.

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Thus, –210 Joule is the required answer.