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Module 5
Module 6
Module 7a
100

State Newton's first law of motion in your own words.

An object in motion (or at rest) will tend to remain in motion (or at rest) until it is acted upon by an outside force.

100

What is required for an object to be in translational equilibrium?

the sum of the forces acting upon it must be equal to zero.
100

An object moves at constant speed. Is the acceleration necessarily zero? Why or why not?

Acceleration is not necessarily zero. In circular motion, the speed is constant, but because the direction is always changing, the velocity changes. Since velocity changes, there is a non-zero acceleration.

200

State Newton's Second Law of Motion in your own words.

When an object is acted on by one or more outside forces, the vector sum of those forces is equal to the mass of the object times the resulting acceleration vetor.

sum F=ma

200

Distinguish between dynamic equilibrium and static equilibrium.

Dynamic: an object is moving, but it has no acceleration.

Static: object is moving and also no acceleration

300

State Newton's third law of motion in your own words.

For every action, there is an equal and opposite reaction.
300

What is tension in physics? With what unit is it measured?

It is the force from a tight string, rope, or chain. Since it is a force, it is measured in Newtons.
400

What is normal force? 

Why is it important in physics?

Fn is the force exerted by a surface supporting an object. Ex: a person standing on a horizontal surface: the normal force is the force with which the surface pushes up, canceling the gravitational force. 

It is primarily used to determine the frictional force

400

What is the difference between torque and force?

Force causes translational acceleration while torque causes rotational acceleration.

500
A physics student is measuring friction coefficients. For one surface, she measures the coefficients but neglects to write down which is the static coefficient and which is the kinetic one. If the numbers are 0.23 and 0.54, which is which?

The static coefficient is always greater, therefore, static is 0.54 and kinetic is 0.23.

500

Before cars came out with power steering, a big car required a much bigger steering wheel than a small car. Why?

The bigger the car, the harder it is to turn the wheels. If the steering wheel is large, the driver grasps the wheel farther from the axis of rotation. This increases the lever arm, allowing the driver to apply more torque to the steering wheel, making it a little easier to turn.