1st Law
2nd Law
3rd Law
The Final Frontier
Jedi Level
100
What is the minimum number of forces that must act on an object on Earth for it to not move?
Two.
100
Archimedes believed that an unbalanced force caused an object to move with velocity? What was wrong with his thinking?
Unbalanced forces cause changes in velocity (aka acceleration).
100
How many forces are involved in any interaction.
Two.
100
Are the forces on an object in orbit balanced or unbalanced?
Unbalanced!
100
A bowling ball and a tennis ball are dropped from a cliff. Model both objects as point particles. Describe any differences in the forces and accelerations of each object.
The gravitational force on the bowling ball is greater than that of the tennis ball by a factor of the ratio of their respective masses. The acceleration of each object is the same.
200
An object will move with constant velocity if the total force is
zero.
200
An object is moving at constant velocity. What can be said about the total force acting on it?
The total force is zero.
200
The two forces in an interaction have the same _______.
magnitude
200
The reason an object orbits the Earth is because it is in a constant state of ________?
freefall
300
A book that is set on a table will not move through the table because
the normal force from the table is balancing the force of gravity.
300
An object has three different forces acting on it. Is it possible for the object to move at constant velocity? If no, say why; If yes, under what condition(s)?
Yes, if the vector sum of forces is zero.
300
I push a box on the floor with 50 N of force. The box does not move because the force the box exerts on me is the same as the force I exert on it. What, if anything, is wrong with this statement?
The statement is true, but it is not why the box does not move. In order to make the box move, you must apply a force greater than the force of friction between the box and the ground.
300
There is no gravity in space. True or False?
False!
400
If you apply a horizontal force to a box which is sliding across a floor equal in magnitude to the frictional force between it and the ground, the box will
move at constant velocity.
400
An object will slow down if the total force acting on it is ______ the direction of its displacement.
opposite
400
When constructing force diagrams, the two forces that make up an interaction are drawn how?
Equal in length(magnitude), but on DIFFERENT objects.
400
Your ________ is the same on the moon as it is on Earth, but your _________ is less.
mass; weight
500
Complete the statement: A falling object will reach _______ velocity because the ________ of the forces acting on it are _______.
terminal; magnitude; equal
500
Is it possible to move at constant speed but still be accelerating? If no, say why; If yes, under what condition(s)?
Yes: change the direction of motion (e.g. move in a circle).
500
You are sitting on a book which resting on a chair that is on the floor. How many forces are acting on the book?
Three.
500
The moon orbits the Earth because of centripetal force. What, if anything, is wrong with this statement?
The moon orbits the Earth because of the gravitational force from the Earth on the moon. This force functions as the centripetal force, but there is no such thing as an actual "centripetal" force.
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