Forces

Question 1

Examples of contact forces

Answer 1

Friction
Air resistance
Tension
Normal contact force

Question 2

Examples of non contact forces

Answer 2

Gravitational force
Electrostatic force
Magnetic force

Question 3

A force can change an object’s…

Answer 3

Speed
Shape
Direction

Question 4

What is a vector quantity?

Answer 4

They have magnitude and direction

Question 5

What is a scalar quantity?

Answer 5

Only have magnitude

Question 6

Examples of scalar quantities

Answer 6

Volume
Distance
Speed
Mass

Question 7

Examples of vector quantities

Answer 7

Force
Velocity
Acceleration
Displacement
Momentum

Question 8

Free body diagrams show…

Answer 8

The forces acting on an object

Question 9

What is a resultant force?

Answer 9

The overall force acting on an object

Question 10

How can you show the magnitude on a free body diagram?

Answer 10

Through the length of each arrow

Question 11

How do you find the resultant force on a scale diagram?

Answer 11

Draw each force tip-to-tail
Measure the distance with a ruler(with a scale)
Measure the bearing

Question 12

What does it mean if the resultant force is 0N?

Answer 12

The forces are balanced

Question 13

If an object has a thrust of 100N and a backwards force of 100N
What does this mean

Answer 13

The object is moving at constant speed

Question 14

What is centre of mass?

Answer 14

The point at which mass can be thought as being concentrated

Question 15

How do you find centre of mass?

Answer 15

Find the crossing of the lines of symmetry

Question 16

What is Hooke’s law?

Answer 16

The extension of a spring is directly proportional to the force applied

As long as the limit of proportionality is not exceeded

Question 17

What is elastic deformation?

Answer 17

Object returns to its original shape after the force is removed

Question 18

What is inelastic deformation?

Answer 18

An object that does not go back to it’s original shape

Question 19

What does ‘elastic limit’ mean?

Answer 19

The point beyond the limit of proportionality where the object will not go back to it’s original shape

Question 20

What is spring constant?

Answer 20

How many newton’s it would take to stretch an object by 1m

Question 21

Force with spring constant formula

Answer 21

F =ke
Force = spring constant×extention

Question 22

On a force extension graph, what deformation occurs when the line is straight?

Answer 22

Elastic deformation

Question 23

What is a moment?

Answer 23

The turning effect of a force that acts around a pivot

Question 24

When an object is balanced…

Answer 24

The anticlockwise moment is equal to the clockwise moment

Question 25

If gear A is rotating clockwise, then what direction is gear B rotating?

Answer 25

Anti-clockwise

Question 26

Low gear means...

Answer 26

Low speed and high turning effect

Question 27

The ratio of the turning effect is equal to the...

Answer 27

Ratio of the radii

Question 28

Equation for moments

Answer 28

M = fd

Question 29

What two things does pressure of a liquid depend on?

Answer 29

Depth Density of the liquid

Question 30

How does upthrust occur?

Answer 30

The bottom of the object experiences more pressure than the top due to the height of the water column

Question 31

What is atmospheric pressure at sea level?

Answer 31

100kPa

Question 32

Acceleration equation

Answer 32

Change in velocity(final-initial)÷time

Question 33

Size of air resistance depends on 2 two things, which are?

Answer 33

Surface area and velocity

Question 34

Terminal velocity is reached when...

Answer 34

The resultant force is 0 The weight has the same magnitude as the air resistance

Question 35

What is Newton's first law?

Answer 35

An object's motion will not change unless a resultant force acts on it

Question 36

What is Newton's second law?

Answer 36

The size of the resultant force is directly proportional to the acceleration it causes

Question 37

What is inertia?

Answer 37

The tendency for the motion of an object to remain unchanged

Question 38

What is Newton's 3rd law?

Answer 38

When two objects interact, the forces they exert on each other are equal and opposite

Question 39

What is thinking distance?

Answer 39

The distance travelled during the driver's reaction time

Question 40

What affects thinking distance?

Answer 40

Reaction time(alcohol, tiredness, etc) Speed

Question 41

What is braking distance?

Answer 41

The distance travelled when braking

Question 42

What affects breaking distance?

Answer 42

Road condition(eg icy) Condition of brakes/tyres Mass of vehicle Speed of vehicle

Question 43

Stopping distance =

Answer 43

Braking distance + thinking distance

Question 44

What is the conservation of linear momentum?

Answer 44

Total momentum before an event is equal to the total momentum after the event