Work
True or False: An unbalanced force doesn't affect motion.
FALSE
The more mass an object has, the more __________ is required to stop it.
Force
If you push an object twice as far without changing the force you pushed it with, what happens to work (increase, decrease, etc.)?
Work doubles!
If Mr. Atkin pushes against the wall with a 50N force for 2 seconds, how much power is she using?
None! No work is done on the wall.
The unit of measurement for force
An object at rest will stay at rest unless this occurs.
Acted upon by an unbalanced force.
If a business man carries a briefcase with an upward force of 10N a distance 5 m to the right, how much work does he do on the briefcase?
He does 0J of work on the briefcase because the force is perpendicular to his displacement
What are two ways that power can be increased? (Hint: Power = Work / Time)
Increase the amount of work done, or decrease the time in which work is done
The more mass an object has the more _________ it has.
Inertia
A car and a large truck are rolling down a hill. Which will take more force to stop it.
Truck
In the equation W = F d, what do each of the variables/letters represent?
W = work
F = force
d = distance traveled
A 50 Newton sack is lifted 2 meters from the ground and a 25 Newton sack is lifted 4 meters. Both were lifted in 10 seconds. Which used up more power?
They are equal!
When an object is not moving it is said to have these forces acting on it.
Balanced forces
It takes more force to move an object with less mass (true or false)
FALSE
The direction of the displacement and the direction of the force are PERPENDICULAR TO EACH OTHER. This means that the amount of work done will be ____.
Zero
An older man and young boy, who each have the same mass of 60 kg, climbed up the top of the same building. The older man, given his age, walked slowly. The young boy walked up faster.
Who did more work?
Who used up more power?
Same work (same mass, same distance traveled)
More power = boy (climbed faster)
The sum of all the forces on an object
Net force
Which of Newton's Laws explains how a rocket works (300 bonus points if you can explain how it works using this law)