Show:
Vocabulary
Newton's First Law
Newton's Second Law
Newton's Third Law
Miscellaneous
100
What is a force?
A push or a pull.
100
What are the three types of friction?
Rolling, Static, and Sliding.
100
What is the formula that goes with Newton's Second Law of Motion?
F = ma or a= F/m
100
What is Newton's Third Law of Motion?
For every action there is an equal but opposite reaction. Or Forces always act in equal but opposite pairs.
100
What three things can happen when an object accelerates?
It can speed up, slow down/stop, or change direction.
200
What are balanced forces?
Two or more forces whose effects cancel each other out.
200
What are 3 ways to reduce friction?
Make surface smoother (ice, water, air, oil), decrease mass of object, or add wheels.
200
What force is needed to make a 7 kg object accelerate at 2.3 m/s2?
16.1 N
200
What are the action-reaction forces that occur when you kick a soccer ball?
Your foot pushes forward and up on the ball. The ball pushes backward and down on your foot.
200
What influences how much gravity affects two objects?
Mass of the objects and the distance between the objects.
300
What is net force?
The total force felt by an object.
300
What is Newton's First Law of Motion?
An object at rest will remain at rest, or an object in motion will continue to move at a constant speed in a straight line, unless acted upon by an outside force.
300
What is the acceleration of an object that has a mass of 145 kg and a force of 942.5 N acting on it?
6.5 m/s2
300
Why are you not able to see the Earth move when you are walking and running?
The Earth has much more mass than you, so it will accelerate much less when the same amount of force acts on it.
300
What do you need to know about a force in order to predict how it will affect an object?
Direction and magnitude of the force.
400
What is friction?
The rubbing force that acts against motion between two touching surface.
400
Why do wheels skid when they hit water?
The water reduces the rolling friction. The wheels lose traction with the ground, causing the object to skid and lose control.
400
How does Newton's Second Law of Motion apply to centripetal force (circular motion)?
With circular motion, an object is constantly changing direction. Therefore, it is constantly accelerating. Newton's Second Law states that you have to apply a force in order for an object to accelerate.
400
Why don't action-reaction forces result in a net force of zero?
Action-reaction forces are not acting on the same object, therefore they cannot cancel each other out.
400
A 45 kg girl pulls a wagon with 15 N of force. How much force is the wagon exerting on the girl?
15 N of force.
500
What is terminal velocity?
The maximum speed an object reaches when the force of gravity downward is balanced by the force of air resistance upward.
500
What is the net force of an object if the following forces are acting on it: 15 N to the left, 10 N up, 12 N to the right, 5 N down, 24 N to the right, 10 N to the left, and 5 N down.
11 N to the right.
500
What is the acceleration of a 1.4 kg object falling through the air, if the force of air resistance acting on the object is 2.5 N? (Multi-step problem)
8.01 m/s2
500
If two bumper cars collide, what are the action-reaction forces? If equal force is applied, after the collision, will both bumper cars have equal acceleration? Explain.
Action-reaction: one car pushes the second car / the second car pushes back on the first car. The accelerations of the two cars will depend on the masses of the cars. A car with more mass will accelerate less than a car with less mass.
500
A 6.5 kg object is pushed across the floor with a force of 38 N. What is the frictional force on the object, if the object's acceleration is 4.2 m/s2?
10.7 N