The combination of all of the forces acting on an object.
100
What equation do we use to represent Newton's second law?
F = ma
100
What is the equation for momentum?
p = mv
100
At what angle should you launch a projectile to achieve maximum distance?
45 degrees
100
You and your friend are pushing a couch across the room. You push with 21 N and your friend pushes with 37 N. What is the Net Force acting on the couch?
58 N
200
What direction does the force of friction act in?
The opposite direction of motion
200
What do we call an object's tendency to resist a change in motion?
Inertia
200
If the action force is a baseball bat hitting a ball, what is the reaction force?
The ball hitting the bat in the opposite direction with the same amount of force.
200
What 2 forces act on a projectile?
Gravity and Air resistance
200
What is a centripetal force? Give an example of one.
Any force that causes an object to move in a circle (or ellipse).
300
What does it mean for forces to be balanced? What is happening to the motion of an object when forces are balanced?
Equal forces in opposite directions on an object. Balanced forces do not change the motion of an object.
300
If you double the force on an object, what happens to its acceleration? If you double the mass, what happens to the acceleration?
When you double the force, the acceleration doubles. When you double the mass, the acceleration is divided in half.
300
You are driving a go-kart and run into your friend's kart. Your friend skids out of control and comes to a stop. Why wasn't the momentum conserved?
The law of conservation of momentum only applies in the absence of outside forces. Friction was acting on your friend's kart, which slowed it to a stop.
300
The force of gravity between you and a car is _________ than the force of gravity between you and Earth because the car has less __________ than the earth.
Weaker, mass
300
As you go grocery shopping, the cart gets harder and harder to push as time goes on. Why?
When you add items to the cart, you increse its mass, which gives it higher inertia and makes it harder to move.
400
Give one example of increasing friction intentionally. Give one example of reducing friction intentionally.
(Various Answers)
400
When you jump, you are pushing down on the Earth. Why do you move instead of the Earth?
The Earth has much more mass, which means it has greater inertia and is harder to move than you are.
400
If you have a 3 kg bowling ball rolling 5 m/s and a 2 kg bowling ball rolling 7 m/s, which one has more momentum?
The 3 kg bowling ball has a higher momentum.
400
What is weight? What units do we use to measure weight?
The force on an object caused by gravity. Measured in Newtons (like ALL forces).
400
How does a space shuttle get into outer space?
A chemical reaction in the engines causes the shuttle to push down on the gases below it. According to Newton's 3rd law, the gases also push up on the shuttle in the opposite direction with the same amount of force. This is called thrust. As long as Thrust is greater than gravity (and air resistance), the shuttle will reach space.
500
A ball and a block of equal mass are sitting on a ramp. The ball rolls down the ramp, but the block stays at rest. Why?
Sliding (or static) friction is stronger than rolling friction. Gravity is affecting both objects the same amount, but the block has a greater force resisting its motion and does not move.
500
You are in the car with your crazy uncle going 120 mi/hr! All of a sudden, he sees a cop and slams on the brakes. What happens to you? Why?
You move forward because there is no force directly acting on you, and your inertia resists the change in motion. If you were wearing a seatbelt, it applies an unbalanced force that stops you from flying forward and hitting the windshield. If not, you are having a very bad day.
500
If action and reaction forces are equal in strength and opposite in direction, why don't they balance?
The forces are acting on different objects. You can only combine forces together when they are acting on the same object.
500
What is the law of universal gravitation?
Every object in the universe is attracted to every other object in the universe by a force called gravity.
500
What are the correct SI units for Mass, Velocity, Acceleration, Momentum, and Force?
Mass = kg (or g), Velocity = m/s, Acceleration = m/s/s, Momentum = kg x m/s/s, Force = Newtons