Force and Laws of motion

An unbalanced net force causes an object to…

move and accelerate.

If an object is not moving, what is the Net force acting on that object?

Zero

Define Newton’s First Law

An object will resist a change in motion until an unbalanced force acts upon it. ‘Law of Inertia’

Newton’s Second Law

An object will accelerate in the direction of the net (unbalanced) force.

What is the formula for force?

F=m x a

What is the acceleration due to gravity here on Earth?

9.8m/s/s

What is Newton’s Law of Universal Gravitation?

The greater the mass, the greater the gravitational pull. The grater the distance, the weaker the gravitational pull.

Gravity

The attractive force exerted by any two masses.

What two factors most affect the force of gravity?

Mass and distance

According to Newton’s second law, what two factors affect the acceleration?

Mass and force

How is the force of gravity related to the distance between the objects?

As distance increases, the gravitational force decreases.

What is air resistance?

A force that acts in the opposite direction of the object’s motion.

What is Terminal Velocity and why does it occur?

The highest velocity an item in free fall with reach.

1. Gravity pulls the object downward.

2. Air resistance (also called drag) pushes upward against the motion.

How much do you weigh?

Divide my pound weight by 2.2 and multiply by 9.8

What is Inertia?

The tendency of an object to resist a change in motion.

Balanced forces

Equal forces in opposite directions that result in a zero net force.

Net force

The result of all forces acting on an object.

Balanced forces are…

equal and in opposite way.

Which has more inertia, a car standing still or the same car in motion?

Neither—both have the same inertia because inertia depends only on mass, not motion.

Inertia

This is a property of matter (mass). The greater the mass of an object, the greater its resistance to a change in motion.

Newton’s third law

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

Absence of air resistance

means everything will drop at the same rate.

On position-time graph, what does the slope tell you?

Velocity

On a velocity-time graph, what does the slope tell you?

Acceleration

Can an object accelerate if there are no net forces?

NO

Can an object be moving with no net force?

YES object in motion remain in motion even when forces are balanced.

If the net force acting on a stationary object is zero, the object will

remain at rest.

A horizontal line on a distance time graph means the object is

not in motion

An upward slope on a distance-time graph means the object is

moving away.

A downward slope on a distance-time graph means the object is

moving towards.