Definitions
Forces
Inertia
F=ma
Action-Reaction
100
A push or a pull on an object
What is a force
100
The amount of force “Applied” to an object
What is the Applied Force
100
Objects at rest stay at rest and objects in motion continue in motion in a ___________ line at a _________ speed unless acted on by an outside force.
What are straight and constant
100
In Newton's second law, F=ma, F and a are _______ related, while m and a are ________ related.
What is directly and inversely
100
What does Newton's law of action-reaction say?
For every action, there is an equal and opposite reaction
200
A mathematical quantity that represents both magnitude and direction
What is a vector
200
The gravitational force on an object
What is Weight
200
The three key scientists in discovering inertia
Who are Aristotle, Galileo, and Newton
200
How much force is needed to accelerate a 2000 kg truck, a 70 kg passenger, and 530 kg of rock 10 m/s^2?
F= 26,000 N.
200
Why don't action and reaction forces cancel each other out?
They are acting on different objects
300
The vector sum of the forces acting on an object
What is the Net Force
300
A force that resists and objects motion
What is Friction
300
An objects inertia is dependent on ________, not its size or volume.
What is mass
300
A cowboy and his horse have a combined mass of 150 kg. If the net force acting on the cowboy and his horse is 450 N, what is their acceleration?
3 m/s^2
300
You are standing on a log in the water at a lake. As you start to walk along the log the log starts to move backwards. As you look to the shore you realize that you are not actually moving forwards. If you continue to walk like this, however, you will eventually run out of log and end up in the water. Explain this in terms of Newton’s Third Law.
Newton's third law says that you are acting on the log pushing it backwards, so that you can walk forward. However, if your surface is less massive than you are, it will accelerate at a greater rate than you, and your position will barely change. You will more or less walk across the log, but push the log behind you, so your position in reference to the log will change, but not in reference to the lake.
400
The measure of an objects resistance to a change in motion
What is Mass
400
The frictional effects of the air on the motion of an object
What is Air Resistance
400
When a bird lets go of a branch and drops to the ground below, why doesn’t the moving earth sweep away from the dropping bird?
The bird is moving at the same speed as the earth, before, during and after the drop.
400
If a force of 20,000 N is needed to push a broken down car with an acceleration of 25 m/s^2, what is the mass of the car?
800 kg
400
A friend is arguing Newton’s Third Law with you. He states that when a bullet fires from a gun there must be an equal and opposite force backward on the bullet and that those forces would cancel each other out. Therefore, he says, there is no way a bullet would be able to move and that means Newton’s Third Law doesn’t work. How would you enlighten your confused friend?
Explain to your friend that the equal and opposite forces means that the gun is acting on the bullet, but then the bullet is acting on the gun. They are acting on each other, or they are NOT acting on the same object, so they can't cancel out.
500
An objects resistance to a change in its motion
What is Inertia
500
The force directed along the length of a wire and pulling equally on the opposite ends of the wire.
What is Tension
500
What kind of path would the planets follow if suddenly their attraction to the sun no longer existed?
Straight line tangent to the orbit.
500
A dog is pulling his 50 kg owner on a 3 kg skateboard with an applied force of 100 N. If there is a frictional force of 47 Newtons, what is the acceleration of the owner on the skateboard?
What is 1 m/s^2
500
A bug splatters on a fast-moving car's windshield. Is the force on the car from the bug the same as the force on the bug from the car? Explain.
The forces are equal, but opposite. This is possible because the mass of the bug is much smaller than the mass of the car, so the bug will experience a greater acceleration due to the force of impact than the car.
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