A36.0 kg crate starting from rest is pulled across a floor with a constant horizontal force of 225 n. for the first 11.0 m the floor is frictionless, and for the nest 10.0 m the coefficient of friction is 0.20. what is the final speed of the crate after being pulled these 21.0 m

We can solve the problem by using conservation of energy.

In the first 11.0 meters, where the floor is frictionless, the kinetic energy gained by the block is equal to the work done by the horizontal force F:


In the second part of 10.0 m, the kinetic energy gained by the block is equal to the work done by the horizontal force F minus the work done by the frictional force:



So, the total kinetic energy gained by the crate in these 21.0 meters is

And since the crate started from rest, this is equal to the final kinetic energy of the crate, so we can calculate its final velocity starting from this value:

Ithink your answer is d

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