## Chapter 3: The Causes of Motion

Hands on: The friction coefficient relates the force required to push something along a surface to the force which presses the surfaces together. How could you measure the friction coefficient? If you exert just enough force overcome friction and start something in motion, do you have to push with that same force to keep it going at a constant speed?

Describe Newton's Laws and their applications to motion.

Given F=ma, calculate the motion of an object

If a 5 kg object is acted upon by a force of 20 N, what is its acceleration? If it starts from rest, what will be its speed after 3 seconds?

What is the difference between mass and weight?

If and object has a mass of 2 kg, what is its weight under normal Earth gravity?

If a crate weighs 120 pounds, what is its mass?

Describe static and kinetic friction and their applications

If the coefficient of static friction of a surface is 0.5 and the coefficient of kinetic friction is 0.4, then how much force will be required to set in motion a 40 kg crate? How much force will be required to keep it going at a constant velocity a after starting?

If a large truck and a Volkswagen collide, which is acted upon by the larger force?

If more than one force acts on an object, how do you predict its motion from Newton's second law?

If a 10 kg object falls in the Earth's gravity but is acted upon by a 40 N air resistance force, what will be its acceleration?

Does motion in a circle at a constant speed involve an acceleration?

What is the difference between centrifugal force and centripetal force? Which can you measure with a scale?

 9 10

*Motion Concepts

*Newton's Laws

*F = ma

*Mass and Weight

*Elevator Problem

*Application of F=ma

*Motion calculation

*Weight calculation

*Friction

*Force to overcome friction

*Newton's 3rd Law

*Combinations of forces

*Centripetal acceleration

*Vector velocities

*Centripetal force calculation

Index
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