Momentum and Force
What is an easy way for second graders to understand the
conceptual difference between momentum and force.
Force makes momentum change. Mathematically, the force on an object
is equal to the rate at which the object's momentum changes.
Not an easy concept to convey to students especially at young age.
You might try the following analogy:
Acceleration is the rate of change (time) of velocity.
This is simple to explain using the concept of acceleration in an
Analogously, force is the rate of change of momentum.
Force is how hard you push or pull on an object. Momentum relates more to
how hard it is to stop an object from moving. A 10mph bowling ball is much
more difficult to stop than a 10mph ping-pong ball. The bowling ball has
Momentum is within an object, carried with the object. Force is between
objects. Momentum is like what the object has in its bank account. Force
is like giving some of this momentum to another object every second they are
in contact. I use "bank account" rather than "wallet" because a bank
account balance can be negative. It allows momentum to have direction.
Click here to return to the Physics Archives
Update: June 2012