Newton's Laws
Inertia is proportional to what quantity?
Mass
A 20 Newton force and a 30 Newton force act on an object in opposite directions. What is the magnitude of the net force on the object?
10 Newtons
What direction does the gravitational force vector always point if you are on Earth?
Down
Also accept: Toward the center of the Earth
A person is traveling at 10 m/s for 5 seconds. What is their acceleration?
2 m/s2
Which has more mass, a kilogram of feathers, a kilogram of water, or a kilogram of lead?
they are all the same
According to Newton's Third Law, if you push something gently, what will the object do?
Gently back on you
What is the net force on a parachute if the force of gravity is 20 N and the force of air resistance is 10N?
10 N down
An egg is falling downward with a force of 10 N. It has reached terminal velocity. In which direction and with what magnitude should the air resistance vector be drawn?
10 N, Up
On the surface of planet X, a body with a mass of 5 kilograms weighs 20 newtons. The magnitude of the acceleration due to gravity on the surface of planet X is
4 m/s2
How would the mass and weight of an object on the Moon compare to the mass and weight of the same object on Earth?
Mass would stay the same. Weight would be more on Earth.
A person who is in free fall while skydiving is attracted to the center of the earth by a 500 N gravitational force. The force with which the earth is attracted to the person is
500 N
10 N down, 20 N left, 30 N up, 40 N right.
What is the net force in the x direction?
20 N right
What does the length of the vector mean on a free-body diagram?
Magnitude
How are acceleration and net force related?
Accept:
F = ma or acceleration and net force are directly proportional to each other
What is true about the forces acting on an object when it reaches terminal velocity?
Forces are balanced.
An object in motion will stay in motion unless what acts on it?
An unbalanced force
If you double the net force on an object but the mass stays the same, what happens to the acceleration?
It doubles.
List all of the forces acting on a car moving at a constant velocity.
Friction, normal, gravitational
A tennis ball and a solid steel ball of the same size are dropped at the same time. In the absence of air resistance, like if the experiment was done on Mars, which ball has the greatest acceleration?
Neither. They have the same acceleration due to gravity.
What is the unit to measure forces?
Newtons
A bug splatters against the windshield of a moving car. Compared to the acceleration of the car, the acceleration of he bug is
Larger
A net force F accelerates a mass m with an acceleration a. If the same net force is applied to mass 2m, then the acceleration will be what?
a/2
List all of the forces acting on a car that is accelerating to the right. List which direction the forces will be balanced.
Friction left, normal force up, force of gravity down, applied force to the right.
Forces are balanced in the x-direction.
When does an object accelerate?
When forces are unbalanced.
What are the units that make up a Newton?
kg x m/s2