Bob is pushing a box across the floor at a constant speed of 1.5 m/s, applying a horizontal force whose magnitude is 50 N. Alice is pushing an identical box across the floor at a constant speed of 3 m/s, applying a horizontal force. (a) What is the magnitude of the force that Alice is applying to the box? F = N

50N

Explanation:

As both boxes are in constant speed (whatever they are), the net acceleration and also net force on them must be 0 according to Newton's 1st law. The force used to push the box is there to counter the friction force, which depends on the normal force and the weight of the box. Since both boxes are identical, their weight are the same, so as the friction force and push force.

Therefore, magnitude of the force that Alice is applying to the box would be the same at 50 N