Question

certain force acting on a 20 kg mass changes itsvelocity from 5m/s to 2m /s calculate the work done by force​

Answer 1

Answer:

-210J

Explanation:

Work Done is Force*Displacement

This formula is analogous to Mass*Acceleration*Displacement

(because Force is mass*acceleration)

$v^{2} -u^{2} = 2as$

So, $s=(v^{2} -u^{2} )\frac{1}{2a}$

As Work = mas,

W = ma ((v^{2} -u^{2} )\frac{1}{2a}[/tex])

Simplifying, we get F=m((v^{2} -u^{2} )\frac{1}{2}[/tex]))

Replacing the values given, F = $20*(2^{2} -5^{2} )/2\\\\20*(-21)/2\\\\-210J$

As, work is negative, we can see that work is done to STOP the motion of the given mass from 5m/s to 2m/s.