suppose you exert 150N on your refrigerator and push it across the kitchen floor at constant velocity.
a. is the friction force equal and opposite to your 150N push? explain
b. does the friction force make up the reaction force to your push?
at constant velocity? No net force.
Netforce= mass*acceleration
pushing force-frictioin= ma
but at constant velocity, a=0, so
pushing force=friction force.
a. In this scenario, if you are pushing the refrigerator at a constant velocity, it means that the net force acting on the refrigerator is zero. According to Newton's first law of motion, an object will remain in a state of rest or in uniform motion in a straight line unless acted upon by an external force. Therefore, the friction force acting on the refrigerator must be equal and opposite to your push of 150N.
Friction is a force that opposes motion and its magnitude depends on the type of surfaces in contact and the normal force (the force exerted perpendicular to the surface due to the weight of the object). Therefore, the friction force exerted on the refrigerator must be exactly 150N in the opposite direction to balance out your push. This ensures that the net force is zero and the refrigerator maintains a constant velocity.
b. No, the friction force does not solely make up the reaction force to your push. It is important to understand that the reaction force to your push is provided by the refrigerator itself. According to Newton's third law of motion, every action has an equal and opposite reaction. So, as you exert a force of 150N on the refrigerator, the refrigerator exerts a reaction force of 150N in the opposite direction on you.
The friction force, on the other hand, arises between the surfaces of the refrigerator and the floor. It is not a direct reaction force to your push but rather a force that arises due to the resistance between the two surfaces in contact. The friction force acts in the opposite direction of the motion and varies based on the coefficient of friction and the normal force. Its purpose is to prevent the refrigerator from sliding or accelerating due to your push.