✅ 5.1 Forces & Interactions

Question 1

What is the difference between scalar and vector quantities?

Answer 1

• Scalar quantities have magnitude/size only
• Vector quantities have magnitude and direction

Question 2

How can vector quantities be represented?

Answer 2

Vector quantities can be represented with an arrow where the length of the arrow represents the magnitude or size and the direction of the arrow represents the direction of the vector quantity

Question 3

List 5 Scalar Quantities

Answer 3

• Mass
• Speed
• Distance
• Energy
• Temperature

Question 4

List 5 vector quantities

Answer 4

• Displacement
• Velocity
• Force
• Weight
• Acceleration

Question 5

What is electrostatic force?

Answer 5

Electrostatic forces is the force exerted between 2 charged objects

Question 6

What is Normal Contact Force?

Answer 6

Normal Contact Force is an upwards force that acts 90° to a surface and is produced when two objects are in direct contact

Question 7

Define a force

Answer 7

A force is a push or pull that acts on an object due to interaction with another object

Question 8

What type of quantity is a force?

Answer 8

A force is a vector quantity as it has both a magnitude and an assosciated direction

Question 9

What are the 2 types of forces?

Explain them

Answer 9

• Contact Forces, which is a force that acts when objects are physically touching
• Non-Contact Forces, which is a force that acts when objects are separated and not physically touching

Question 10

Give 4 examples of contact forces

Answer 10

• Friction
• Air resistance
• Tension
• Normal contact force

Question 11

Give 3 examples of non-contact forces

Answer 11

• Graviational Force
• Electrostatic force
• Magnetic force

Question 12

What is gravity?

Answer 12

Gravity is the force of attraction between all objects

Question 13

What is mass?

What are its units of measurement?

Answer 13

Mass is the amount of matter than an object contains

It is measured in kg

Question 14

What is weight?

What is it measured in?

Answer 14

Weight is the force acting on an object due to gravity

Weight is measured in (N) Newtons

Question 15

What causes the force of gravity close to the Earth?

Answer 15

The force of gravity close to the Earth is due to the gravitational field around the Earth

Question 16

What do all planets have in common?

Answer 16

All planets have strong gravitational fields

Question 17

What two factors does the weight of an object depend on?

Answer 17

The weight of an object depends on:
- The mass of the object
- The gravitational field strength of the location where the object is in

Question 18

What is the formula for calculating the weight of an object?

Answer 18

The weight of an object can be calculated using the equation:
Weight = mass x gravitational field strength
W = mg
————————————————————
W - N
M - kg
G - N/Kg

Question 19

Describe the relationship between the weight and mass of an object

Answer 19

The weight and mass of an object are directly proportional

Question 20

How can the weight of an object be measured?

Answer 20

The weight of an object can be measured using a newtonmeter, which is a calibrated spring balance

Question 21

How does a calibrated spring balance work?

Answer 21

• The object is attatched to the end of the hook
• The spring will stretch a fixed distance for each newton

Question 22

Where does the weight of an object act?

Answer 22

The weight of an object acts at a single point known as the centre of mass

Question 23

What is the centre of mass?

Answer 23

The centre of mass is the single point at which the weight of an object is considered to act

Question 24

How can we find the centre of mass for a regular shape?

Answer 24

The centre of mass of a regular shape can be found using the lines of symmetry

Question 25

How can we find the centre of mass for an irregular object?

Answer 25

The centre of mass for an irregular object can be found by locating its balance point

Question 26

What is a resultant force?

Answer 26

A resultant force is a single force that replaces a number of forces acting on an object, because it has the same effect as all of the original forces acting together

Question 27

What are balanced forces?

Answer 27

Balanced forces are when the resultant force of an object is zero, and the object is either stationary or moving at a constant speed

Question 28

Do questions on free body diagrams

Question 29

Explain what resolving forces are

Answer 29

A single force acting at an angle can be resolved into a horizontal and vertical force.

Question 30

Do questions on resolving forces

Question 31

What does it mean if an object is in equilibrium?

Answer 31

• The resultant force acting on the object is 0
• There forces acting on the object have no overall turning effect (moments)

Question 32

What is thrust?

Answer 32

Thrust is a type of force that causes an object to move
(e.g car engine / aeroplane)

Question 33

What is air resistance / drag?

Answer 33

Air resistance or drag is the friction of the air on a moving object

Question 34

What is upthrust?

Answer 34

Upthrust is the force of a fluid pushing an object upwards

Question 35

What is comression?

Answer 35

Compression is the forces that act inwards on an object, squeezing it

Question 36

What is tension?

Answer 36

Tension is the force transmitted through a cable or string when pulled on by forces acting on opposite ends

Question 37

What is the reaction force?

Answer 37

Reaction force is a force due to contact between 2 objects

Question 38

What is friction?

Answer 38

Friction is a force that opposes motion when objects rub against each other