Answer:
The required work done is 
Explanation:
Consider 'F' is the applied force on the crate and 'f' be the force created by friction. According to the figure if '
' be the coefficient of friction, then

where 'M', 'N' and 'g' are the mass of the crate, the normal force aced upon the block and the acceleration due to gravity respectively.
Since the application of force by the movers does not create any acceleration to the block, we can write

So the work done (W) in moving the crate by a distance s = 10.6 m is

the above three pictures may help you
go through the attachments
Answer:
They would land at the same time
Explanation:
They would land at the same exact time.
As weird, impossible and unbelievable as it appears. When in a vacuum, every weight, body and material when released from the same height would land on the ground at the same time. This also means that like in the question, a feather and a ball would land at the same time. And just for illustrations as well, a feather and a car would land at the same time as well.
Answer:
As velocity is uniform then acceleration will be zero.
Explanation: