Unit 2 Review

How do net forces affect an object’s motion?

•If forces are balanced the object’s motion will not change

•If the forces are unbalanced the object’s motion will  start moving, stop moving, or change direction.

How does friction affect an object’s motion?

•Friction is the force that resists motion between two surfaces that are  touching

•Friction is almost always the unbalanced force that stops an object’s motion

How does gravity affect falling objects?

 

What is the difference between weight and mass?

•Weight is a measure of the gravitational force on an object, it can change with the location on an object in the universe.

•Mass is a measure of the amount of matter in an object and will not  change no matter where you go.  

How can Newton’s three laws of motion be used to predict a situation?

• Newton’s 1st law: An object at rest remains at rest, and an object in motion remains in motion at a constant speed and in a straight line unless acted on by an unbalanced force. 
• Ernie on the Skateboard without a seat belt
• Newton’s 2nd law: The acceleration of an object depends on the mass of the object and the amount of force applied.
• Less Force / More Mass = Less Acceleration
• More Force / Less Mass = More Acceleration
• An object has a mass of 15 kg and an acceleration of 10 m/s2. What is the force on the object?
•  Force = 150 N
• An object with a mass of 10 kg experiences a force of 20 N. What is the acceleration of the object? 
•  Acceleration = 2 m/s2
• Newton’s 3rd law: Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.
•  For every action, there is a reaction
• Two people on a skateboard and one pushed the other one