PY 131 Chapter 4/5: Newton's Second and Third Law of Motion

What is inertia?

The property of an object to resist changes to its motion. NOT a force.

What did Galileo observe about objects and their motion?

Objects resist changes to their motion.

What does an object at rest resist?

Efforts to start it moving.

What does an object in motion resist?

Efforts to change its velocity.

What types of motion can an object have?

Linear, rotational, and vibrational motion.

What is an object’s inertia in linear motion?

It is the same as its mass.

What is Newton’s First Law?

It is sometimes called The Law of Inertia.

What does Newton’s First Law imply?

It implies that force is related to acceleration.

What is the relationship between force and acceleration?

The acceleration is in the same direction as the force, proportional to its size, and inversely proportional to the object’s inertia.

What is Newton’s Second Law of Motion?

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to the object's mass.

What is the direction of acceleration?

In the direction of the net force acting on the object.

What is the formula for Newton’s Second Law of Motion?

a = Fnet/m.

What is the SI unit of force?

the newton (N).

What is one newton?

The amount of force required to accelerate an object of mass 1 kg by 1 m/s^2.

What do we need to use Newton’s Second Law?

We need to compute the net force.

What should we do if the forces are not all along the same line?

We should break them down into components.

What cancels out in the y direction?

The components of the forces.

What happens if the maximum static friction is surpassed?

The friction will become kinetic friction.

What is rolling friction?

A different kind of friction that occurs when an object rolls upon another without slipping.

What is drag force?

The force exerted by a fluid upon an object as it moves through it

What does the drag force depend on?

The shape/size of the object, the speed of the object, and the properties of the fluid such as its viscosity and density.