1.

Certain force acting on a 20 kg mass changes its velocity from 5ms^(-1) to 2ms^(-1). Calculate the work done by the force.

Answer»


Solution :Here, `m=20kg, u=5ms^(-1), v=2ms^(-1),W=?`
The work DONE by the force
= change in kinetic ENERGY
= Final `E_(k)` - Initial `E_(k)`
`=(1)/(2)MV^(2)-(1)/(2)m u^(2)`
`=(1)/(2)m(v^(2)-u^(2))`
`=(1)/(2)m(v^(2)-u^(2))`
`=(1)/(2)xx20xx[(2)^(2)-(5)^(2)]`
`=10xx(4-25)=10xx(-21)=-210J`


Discussion

No Comment Found

Related InterviewSolutions