Physics - Lesson 3 + Free Body Diagrams

A rightward force is applied to a book in order to move it across a desk at constant velocity. Consider frictional forces. Neglect air resistance. A free-body diagram for this situation looks like this:

Image as shown

When mass increases, by how much does gravity increase? What is the relationship?

By the same amount, because they are directly proportional

When distance ______ gravity increases by what factor? What is that relationship?

When distance *DECREASES*, gravity increases by *4 times*. It is an inversely proportional relationship.

What is ALWAYS the independent variable?

X axis variable

What are the 4 types of friction?

They are: static friction, sliding friction, rolling friction, and fluid friction.

Static Friction definition?

Static friction is defined as the frictional force that acts between the surfaces when they are at rest with respect to each other. EXP: Table lamp resting on the table.

Sliding Friction Definition?

Sliding friction is defined as the resistance that is created between any two objects when they are sliding against each other. EXP: Two cards sliding against each other in a deck.

Rolling Friction definition?

Rolling friction is defined as the force which resists the motion of a ball or wheel and is the weakest types of friction. EXP: Rolling of the log on the ground

Fluid Friction?

Fluid friction is defined as when a solid object bases through a liquid or a gas: the friction strength is dependant on the "thickness" or viscosity of the conditions. EXP: Swimming in a lake

How many grams are in 1 Newton?

100g per Newton

Can you have side arrows canceled if the free body diagram has a constant SPEED?

Yes

Can you have side arrows canceled if it says constant VELOCITY?

No, velocity implies movement even when it is constant

Reinforce:

Two forces acting on an object in the same direction combine into one stronger force

Counteract:

Two forces acting on an object from opposite directions counteract each other. The direction of motion goes in the direction of the STRONGER force.

Cancel:

When forces are equal and opposite to one another, they are balanced and there is no effect on the motion of the object.