MECHANICS

Module 1

Calculate 2.897 × 20 giving the result to 3 significant figures

57.9

The Scientific Method derived from an astronomer, philosophist and physicist by the name of ________

Galileo Galilei

The Scientific Method follows the order of

1. Observation

2. __________

3. Experiment

4. __________

Hypothesis

Conclusion

What are random errors?

Errors that occur due to unpredictable fluctuations in measurements, leading to differing results when repeated under the same conditions.

State 2 factors that may affect the period of a simple pendulum

1. Length of the string

2. Angle of release

How does the length of the string affect the period of a pendulum?

The length of the string directly influences the period; longer strings result in a longer period, while shorter strings lead to a shorter period.

What is the ‘period (T)’ of a simple pendulum?

The time taken for one complete oscillation of the pendulum, defined as the interval between two successive points of maximum displacement in the same direction.

All non 0 integers are ______

significant

Trailing zeros are significant only if______

there is a decimal point present

Captive zeros are?

zeros between non-zero digits and are always significant.

How many significant figures are in the number 506.709

6

There are _ significant figures in 8.70

3

State the 2 types of errors that can occur amongst measurements

random and systematic errors

What type of error is a parallax error

random error

List 3 ways to correct/prevent a parallax error

If using a vertical measuring instrument, e.g a measuring cylinder, the measurement should be taken at eye level

Use tools with clear measurement indicators

Observations should be made with the line of sight perpendicular to the scale

What are systematic errors?

Systematic errors are those which make the result always too small or always too large by the same amount. They are usually caused by some problem within the measuring instrument

State 2 ways systematic errors can be reduced

• The value of the error must be discovered and then added or subtracted from each reading.

• The instrument must be adjusted.

State the reading on the vernier caliper

3.55

State the reading on the micrometer screw gauge

6.12

State 3 things a micrometer screw gauge can measure

the diameter of wires, the thickness of sheets, the width of a hair strand

Why might a metre rule be chosen over a 30cm rule to measure an object?

The metre rule can measure larger objects or distances compared to a 30cm rule, making it more versatile for various applications. Additionally, it provides greater accuracy and readability for longer measurements.

What is the formula for the density of an object?

Density = mass/volume

Define the term ‘density’

Density is the mass of an object per unit volume.

How can the density of an irregular shaped object be determined?

The density of an irregularly shaped object can be determined by measuring its mass and calculating its volume using water displacement, where the volume is equal to the amount of water displaced when the object is submerged.

The unit for density is ___

kilograms per cubic meter (kg/m³)

or

grams per cubic centimetre (g/cm³)

What are vector quantities?

Vector quantities are quantities that have magnitude and direction

What are scalar quantities?

Scalar quantities are quantities that only have magnitude

List 3 examples of vector quantities

displacement, force, acceleration, velocity and momentum.

Mass, Distance/Length and temperature are _____ quantities

scalar

If vectors are parallel to each other then you can ___ or ______ to find the resultant

add or subtract

When vectors are at right angles to each other, _______ _____ can be used to find the resultant

Pythagoras’ theorem

Briefly explain the parallelogram rule which is used to find the resultant of non parallel vectors

The parallelogram rule requires a scale diagram. Two adjacent sides of the parallelogram represent the two vectors to be combined. Those 2 sides are then copied to scale to complete the parallelogram. The resultant is identified by the diagonal formed starting at the point of intersection of the 2 original vectors and is drawn from this intersection point to the opposite corner of the parallelogram.

A force can cause a change in the ____,____ or _____ of a body

size, shape or motion

What is a magnetic force?

A magnetic force is an attractive or repulsive force existing between bodies due to their magnetic properties

What is an electrostatic force?

An electrostatic force is a force existing between bodies due to their electric charge

The nucleus of an atom is held together by strong _______ ____

nuclear forces

The mechanical force that opposes the relative motion of the surfaces of bodies in contact is called ______

frictional force/friction

On earth, the generally accepted value of gravitational field strength is

10 N/kg

Weight = ___ x _____________

mass x gravitational field strength

Determine the mass of a football which has a weight of 0.80N on a planted where the acceleration due to gravity is 2.0ms^-²

To find the mass, use the formula: mass = weight / gravitational field strength. Thus, the mass is 0.80N / 2.0m/s² = 0.40 kg.

The unit kgms^-2 is used to measure ____

Force

4500 is written as ___ x ____ in standard form

4.5 x 10³

Identify 3 real life examples of situations in which the application of a force will result in a turning effect

1. Opening a door,

2. Using a wrench to turn a bolt

3. Pushing a merry-go-round

4. Sitting on a seesaw

What is meant by the ‘moment (T) of a force’?

The ‘moment’ of a force is the turning effect created when a force acts upon an object at a distance from a pivot point

The unit for moments is ___

Newton-meter (Nm)

T = F x __

d (distance from pivot)

Calculate the force

6N

When describing the action of moments the terms _____ and _______ are used to describe the direction of action

clockwise and counterclockwise/anticlockwise

State the two conditions required for an object to be in ‘equilibrium’

1. There is no resultant force acting on the object

2. The clockwise moment equals the counterclockwise moment.

What is the PRINCIPLE OF MOMENTS?

The principle that for an object in equilibrium, the sum of the clockwise moments about a pivot equals the sum of the counterclockwise moments.

A seesaw, scissors and a nail claw hammer are ___ ____ levers

first-class

First class levers have the _____ in between the effort and the load

fulcrum

Second class levers such as wheelbarrows and a diving board have the ____ between the fulcrum and the ______

load; effort

A bottle opener is a ____ ____ lever

second-class

A second-class lever is used to _____ force

amplify or increase

A fishing rod is a ____ ____ lever

third-class

The aim of a third class lever is to…

Increase the distance over which force is applied, allowing for greater speed or range of motion.

A third class lever has the _____ between the _____ and the fulcrum

effort between the load

The _____ __ _____ is the point from which the weight appears to act.

center of gravity

How can the centre of gravity of an irregular shaped lamina be determined?

By balancing it on a point or using plumb lines to locate the central point

What is stable equilibrium?

Stable equilibrium is a state where a body returns to its original position after being displaced slightly. It occurs when any disturbance raises the objects center of gravity

What is unstable equilibrium?

Unstable equilibrium is a state where a body does not return to its original position after being displaced slightly or in other words it falls over. It occurs when any disturbance lowers the object's center of gravity.

What is neutral equilibrium?

Neutral equilibrium is a state where a body remains in the same position after being displaced, with no tendency to return or topple over. This occurs when the center of gravity remains unchanged.

State 3 factors that affect the stability of an object

1. The width of its base

2. Its weight

3. The height of its center of gravity.

Why do cargo buses have their baggage compartments under the floor instead of on the top?

Cargo buses have their baggage compartments under the floor to lower the center of gravity, enhancing stability and reducing the risk of tipping during operation.