Unit 17.2: Mechanics (Theory 2)

part 2

Giga (G)

10^9

Mega (M)

10^6

kilo (k)

10³

centi ( c )

10^-2

milli (m)

10^-3

micro (μ)

10^-6

nano (n)

10^-9

What quantity is speed?

Scalar (only quantity)

What quantity is velocity?

Vector (as it has direction)

Formula for speed?

Distance ÷ Time

Formula for velocity?

Final displacement ÷ Time taken

Formula for acceleration?

Change in velocity ÷ time

How to calculate change in velocity?

Final velocity - initial velocity

How to convert from m/s to km/hr?

3.6 x m/s

How to convert from km/hr to m/s?

km/hr ÷ 3.6

What is the formula for force?

Mass x Acceleration

What is the formula for weight?

Mass x Gravity (10m/s²)

How to get speed from distance time graphs?

Gradient of line (rise ÷ run)

On x-time graphs, time is always on which axis?

X axis

What is a tangent?

Draw a straight line that touches a curve (used to find speed as curved line = accelerating/decelerating)

In a velocity time graph, the gradient = ?

acceleration of object

How do you calculate displacement on a velocity time graph?

Calculate the area under on a velocity time graph

Density is directly proportional to?

Mass

Density is inversely proportional to?

Volume

What is Newton’s First Law?

An object will stay at rest or move with constant velocity unless an unbalanced force acts.

What is Newton’s Second Law?

When an unbalanced force does act, the object will accelerate where F = MA
So, Acceleration ∝ Resultant Force
and Acceleration ∝ 1/Mass (inversely proportional)

What is Newton’s Third Law?

Every action has an equal and opposite reaction.