Afarmer tosses a rope over a beam at the top of a barn. he ties one end of the rope to a bale of hay. he then raises the bale up to the barn loft by pulling down on the loose end of the rope.

why does the input force have to be greater than the force needed to lift the bale?

a. friction increase the effect of the input force.
b. friction eliminates the work input.
c. friction reduces the work input

C. Friction reduces the work input

Explanation:

When a farmer tosses a rope over a beam at the top of a barn. He ties one end of the rope to a bale of hay. He then raises the bale up to the barn loft by pulling down on the loose end of the rope.

Now during this whole process we know that the friction force present on the barn will resist the motion of rope over it due to which our net force on the rope is reduced.

So here our work done on the rope will be decreased due to the effect of friction as it is opposite to our applied force.

So here we can say that the correct answer will be

C. Friction reduces the work input

the device is called “ rocket engine”

in physics zero. in muscle fatigue could be high