iGCSE Physics - 1. F&M (Y10) - Forces

The two types of forces are...

contact and non-contact

Friction, air resistance, and normal force are all examples of...

resistive forces

Name as many forces as you can

Forces can make objects...

Change speed
Change direction
Change shape

The unit of force is...

Newtons (N)

Newton's First Law states...

an object in motion will stay in motion, and an object at rest will stay at rest, unless acted upon by a resultant force

Newton's Second Law states...

the acceleration of an object is directly proportional to the resultant force on it, and inversely proportional to its mass

Newton's Second Law as an equation is...

Force = Mass x Acceleration

The acceleration of a 12kg object being pushed with a force of 6N is...

a = F/m = 6/12 = 0.5m/s^2

Newton's Third Law states...

for every force exerted on an object, the object will exert an equal and opposite force back

The Third Law paired force with Earth's gravitational force pulling you down is...

your own gravitational force pulling the Earth up

The Third Law paired force with the normal force on you from your chair keeping you up is...

your butt's normal force pushing down on the chair

The Third Law paired force with the thrust of an aeroplane's engines pushing it forward is...

the thrust force on the air being expelled from the back of the engine

If an object is at rest, the forces on it must be...

balanced

If an object is moving at a constant speed, the forces on it must be...

balanced

If an object is moving at a changing speed, the forces on it must be...

unbalanced

If an object is changing direction, the forces on it by be...

unbalanced

The definition of mass is...

the amount of matter in an object

The unit of mass is...

kg (kilograms)

The definition of weight is...

the force of gravity on an object

The unit of weight is...

N (Newtons)

The equation linking mass and weight is...

Weight = Mass x Gravity

The definition of gravity is...

the acceleration of an object due to it's weight in freefall

The unit of gravity is...

m/s^2 or N/kg

Gravity on Earth is...

10N/kg

The gravity of a planet is dependent on its...

Mass (NOT SIZE)

Hooke's Law states that...

the extension of an elastic object is directly proportional to the force on it

Hooke's Law as an equation is...

Force = extension x spring constant

The greater the spring constant, the ____________ the spring is

harder to stretch

The definition of extension is...

the change in length of the spring (new length - original length)

The point at which the spring stops obeying Hooke's Law is called...

the limit of proportionality

You can tell when a spring stops obeying Hooke's Law from the graph by...

the graph is no longer a straight line

A change in shape that can be undone (before the limit of proportionality) is called...

elastic deformation

A change in shape that is permanent (after the limit of proportionality) is called...

plastic deformation