# Physics: UNIT 2

What is the difference between distance and displacement?

Distance is the length between two points while displacement is the distance between points in a specific direction

What is the gradient of a straight horizontal line in a DISTANCE-TIME graph?

Zero

The gradient of a uniformly increasing VELOCITY-TIME graph is...

Acceleration

How do you find the distance under a graph?

Find the area of the shapes under the graph
Triangle = 1/2 (bxh)
Rectangle = l x w

Name 3 examples of a scalar quantity

Any 3: Mass, Time, Length, Area, Volume, Temperature etc.

Name 3 examples of a vector quantity

Any 3: Velocity, acceleration, Force, weight, displacement

What is a scalar quantity?

A quantity that has only magnitude

What is a vector quantity?

a quantity that has both magnitude and direction

When adding vectors, left/west and down/ south are positive or negative?

NEGATIVE

When adding vectors, right/east and up/north are positive or negative?

POSITIVE

What is a force?

a push or pull on an object

Name 3 examples of contact forces

Any 3: normal force, applied force, air resistance, tension, friction, weight, friction

Name 3 examples of non-contact forces

Gravity, magnetic force, electrical force

State 2 effects of forces

Any 2: Change in speed, Change in state of motion, Change in shape/size, Change in direction

Allows vehicles to brake
Allows us to walk/run

Name 2 effects of friction

Heat
Wear and tear

An example of a simple machine is

Choose any: wheel, lever, pulley

What formula is associated with Newton's 2nd law?

F = ma

What does directly proportional mean?

Directly proportional means that an increase in one variable results in an increase in the other variable, or a decrease in one variable results in a decrease in the other variable.

In Newton's 2nd law, what direction does acceleration act in?

Acceleration acts in the same direction as the force

State Newton's third law of motion.

For every action there is an equal but opposite reaction

What 2 conditions are necessary for equilibrium to occur?

Net force must be equal to 0
Sum of all moments must be equal to 0

What is the formula for moments?

Moment = force x distance

Define energy

the ability to do work

Define kinetic energy

the energy an object has due to its motion