Before spring break, we had two days to talk about work and energy in physics class. Today, we are talking about momentum. For their online pre-class reading quiz, I decided to throw in the following question:
Explain what you think the major difference is between energy and momentum. Why do you think we need both concepts?
Here is a sample of student responses.
Momentum deals with mass and velocity, while energy deals with the work done over a period of time.
Momentum measures the ability of an object to continue moving in the same direction with the same speed, while energy measures the amount of force which an object has due to its mass and velocity.
Energy does not involve a collision specifically, it can be potential or kinetic. while momentum does involve a collision.
Energy is what it takes for something to move and momentum is how fast something is moving when it hits something else.
Energy is the capable of work and momentum is a mass in a motion. we need them both because without the work of energy we can not move a object and with out momentum we do not have enough force to keep the object from going fast or to slow down.
Energy is a transferable unit which can be stored and changed into other forms where as momentum is the directional energy that an object has due to its motion.
Energy is a scalor, and momentum is a vector. Energy is measured in foot pounds while momentum is in Joules. We need both concepts in order to find all possible answers for a problem
Momentum is needed to make energy and vice versa. Conservation of energy when collision. Momentum of energy during movement.
Energy is a scalar quantity only expressing magnitude, momentum is a vector quantity and has a magnitude and direction. We need both because they represent different values in the same way that speed and velocity are not the same.
Momentum is a vector and energy is not. Energy can be converted in other forms of energy, while linear momentum can be converted only in linear momentum.
Energy is length times force while momentum is mass times velocity. We need to know both concepts to figure out things we do daily in life.