Week 1 forces and scientific notation

What is a force?

A mutual interaction between two objects

Forces always occur in ?

Pairs (cannot occur in isolation)

Which direction and magnitude do forces occur in?

OPPOSITE direction, and SAME magnitude

Do forces act simultaneously or at different times to each other?

Simultaneously

Unit for force

Newton (N)

Properties of Forces: type

Forces pairs are of the same type

Properties of Forces: magnitude?

SAME magnitude

Properties of Forces: direction?

OPPOSITE direction

What does it mean when a forces is the same type? Give examples

When both forces are the same type, e.g. pull and pull | push and push | gravitational and gravitational | electrical and electrical

force pair of a push force

Push

velocity measures

A change in displacement (∆s) over a change in time (∆t)

Velocity equation

∆s÷∆t

Speed measures?

The distance travelled (d) over the change in time (∆t)

Speed equation

d÷∆t

a scaler quantity

A quantity that has a MAGNITUDE ONLY

What are some examples of scaler quantities?

Mass e.g. kg

Volume e.g. L

temperature

a vector quantity?

A quantity that has a Magnitude and a Direction

What are some examples of vector quantities?

Velocity (v), acceleration (a), gravity, Force

How are vectors expressed

arrows

Equation for acceleration (a)

∆v/∆t

Unit for acceleration (a)

m/s/s = m/s² = ms^-2

Unit for velocity (v)

m/s = ms-1

Why do objects accelerate (move)

Objects accelerate because of an unbalanced force acting on the object

Inertia?

The reluctance of an object to change its state of motion

Change in state of motion?

Acceleration

Newton's 2nd law definition words

Acceleration depends:

1. Directly on the unbalanced or net Force

2. Inversely on the objects mass, M

Newton's 2nd Law equation

Ma=Fnet

Objects with a larger surface move how

Slower

What affect does a parachute have on drag force and terminal velocity

Increases drag force, therefore, reduces terminal velocity

Explain terminal velocity

When an object is still moving at its same speed, just not getting any faster

Why does more surface area increase drag and reduce terminal velocity

Because the maximum speed object can reach is lower

Free body diagram step 1

Start with force pair diagram

Free body diagram step 2

Isolate object of interest

FBD step 3

Add to the object, only those forces directly affecting the object

FBD step 4

Treating the forces as vectors, find the net Force

What is the net force of an object during terminal velocity

0 N

What is acceleration at terminal velocity

a = 0km/h²

What is Velocity at terminal velocity

Remains the same speed

What is the inverse relationship between acceleration and Mass

As Mass increase, acceleration decreases

What is the direct relationship between acceleration and Force

As acceleration increases, Force increases

Unit for weight (same as force)

Newton (N)

Formula/equation for weight

mass × gravity=

m×g

What is weight definition

Force exerted on mass by gravity