What is the kinetic energy of an object that moves at 8 millisecond and weighs 6.7 kilograms

That question can't be answered with the given information.

The kinetic energy of any moving object is

           (1/2) (mass) (speed)² .

You haven't told us the speed of your object, or
anything that we can use to figure it out.

"8 millisecond" is a period of time, not speed.

Attach the free body diagram and i will you answer the question.! : d