A 2.0 kg cart rolls along a lab track at 3.0 m/s. You have seen the two things that make a mover hard to stop: its mass, and its speed.
One quantity measures the two together. What is it?
You have seen that more mass makes a mover harder to stop, and that more speed does too.
Here is the lab cart again: mass 2.0 kg, velocity 3.0 m/s. One number should measure how hard it is to stop.
Multiply the mass by the velocity: 2.0 × 3.0 = 6.0. That single number counts both.
One equation says that move for every object.
momentum = mass × velocity
In symbols: p = mv.
The product mv measures how hard a moving object is to stop. This product is called the object's momentum.
With mass in kilograms and velocity in meters per second, the cart's momentum is written 6.0 kg·m/s.
A 3.0 kg wagon rolls at 2.5 m/s. Enter its momentum in kg·m/s.
More mass means more momentum. More velocity means more momentum. And more momentum means harder to stop.
Celia says: 'Of two rolling carts, the one with more momentum is harder to stop.' Is Celia correct?
Momentum's symbol is a lowercase p. Later in the course, a capital P will name power, so where the two could meet, this course writes the word power out in full.
A 0.60 kg basketball moves at 5.0 m/s. State its momentum.
Write down the values:
m = 0.60 kg, v = 5.0 m/s, p = ?
Write down the equation:
p = mv
Substitute in the values, and calculate:
p = 0.60 × 5.0 = 3.0
The basketball's momentum is 3.0 kg·m/s.
The same basketball is passed faster, at 8.0 m/s. State its momentum now.
Write down the values:
m = 0.60 kg, v = 8.0 m/s, p = ?
Write down the equation:
p = mv
Substitute in the values, and calculate:
p = 0.60 × 8.0 = 4.8
The basketball's momentum is now 4.8 kg·m/s. More speed, more momentum.
A 55 kg sprinter runs at 9.0 m/s. Enter the sprinter's momentum in kg·m/s.
Which statement says what an object's momentum is?
Two identical 20 kg carts roll along a hallway, one at 4.0 m/s and one at 2.0 m/s. Which statement is correct?
Mass multiplied by velocity measures how hard a moving object is to stop. What is this product called?