Question

- A fridge has a maximum static friction force

he 250 N. Sam can push the fridge with a
force of 130N. Amir and André can each
push with 65.N. How could they all move
the fridge? Will the fridge move with constant
velocity? Why or why not?

Answer 1

They will move the fridge if they all push in the same direction, but it will not move with constant velocity

Step-by-step explanation:

The maximum static friction force is

`F_f = -250 N` (negative sign since its direction is opposite to the push applied by the people)

Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:

`F=130 + 65 +65=260 N`

This force is larger than the frictional force, so the fridge will start moving.

However, the net force on the fridge will be:

`\sum F = 260 N - 250 N = 10 N`

And according to Newton's second law,

`\sum F = ma`

where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.