Question

An object starts from rest and moves a distance d due to the presence of a net force F_net . If the net force is doubled ( F'_net = 2F_net ) while keeping the same distance d , then which of the statements below cannot be true ?

Answer 1

Given data:

The net force in case I is F_net.

The net force in case II is F'_net=2F_net.

The distance traveled is d.

The work energy theorem is given by,

`KE=W`

Here, KE is the kinetic energy, and W is the work done.

The work done in case I is,

`W=F_(net)d`

The work done in case II is,

`\begin{gathered} W^(\prime)=F^(\prime)_(net)d \\ W^(\prime)=2F_(net)d \end{gathered}`

The ratio of kinetic energy will be,

`\begin{gathered} (KE)/(KE^(\prime))=(W)/(W^(\prime)) \\ (KE)/(KE^(\prime))=(F_(net)d)/(2F_(net)d) \\ KE^(\prime)=2KE \end{gathered}`

Thus, the final kinetic energy is doubled.

Final Answer:

Its final kinetic energy is doubled.