DC -- Newton's second law

A change in velocity means ---

• there is an acceleration

• gravity is negligible

• there is no friction

• the direction of the force vector is positive

You must define the boundaries of the system before you can determine what?

• which direction is the velocity

• which forces are external

• which direction is gravity

• which forces are negligible

The system of interest is ---

• the mother applying a force

• the wagon only

• the wagon and its rider

• the rider only

What are the vertical forces in this system?

• friction and applied force

• gravity and friction

• mass and velocity

• weight and normal force

The symbol ∝ means --

• exponentially related to

• indirectly related to

• equivalent to

• proportional to

Once the system of interest is chosen, it is important to identify the external forces and ignore ___

• speed

• gravity

• internal forces

• frictional forces

The larger the mass (the inertia), the smaller the ---

• acceleration

• force of gravity on the system

• force of friction

• tension

This diagram illustrates what?

• The same mass at the same acceleration produces different forces.

• The same force exerted on systems of different masses produces different accelerations.

• The same acceleration by systems of different masses produces different forces.