Forces and their interactions

Question 1

What are the types of quantities?

Answer 1

Scalar quantity

Vector quantity

Question 2

What is a scalar quantity?

Answer 2

Physical quantities that have size (magnitude), but no specific direction

Question 3

What are some examples of scalar quantities?

Answer 3

Speed
Distance
Time
Mass
Energy
Power
Density
Temperature

Question 4

What is a vector quantity?

Answer 4

Physical quantities that have direction; they have both magnitude and direction

Question 5

What are some examples of vector quantities?

Answer 5

Acceleration 
Force
Velocity
Momentum
Weight
Gravitational field strength
Displacement

Question 6

How are vectors represented?

Answer 6

Using an arrow
The length of the arrow = the magnitude of the vector
The direction of the arrow = the direction of the vector

Question 7

What is displacement?

Answer 7

Distance in a given direction

Question 8

What is velocity?

Answer 8

Speed in a given direction

Question 9

What is the difference between acceleration and velocity?

Answer 9

Velocity is the rate of change of displacement. Acceleration is the rate of change of velocity.

Question 10

Why is acceleration and velocity a vector quantity?

Answer 10

Velocity is a vector quantity because it consists of both magnitude and direction. Acceleration is also a vector quantity as it is just the rate of change of velocity.

Question 11

What is a force?

Answer 11

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

Question 12

What are the types of forces?

Answer 12

Contact force

Non-contact force

Question 13

What is a contact force?

Answer 13

A force which acts between objects that are physically touching

Question 14

What are some examples of contact forces?

Answer 14

Friction
Air resistance
Tension
Reaction force

Question 15

What is a non-contact force?

Answer 15

A force which acts at a distance, without any contact between bodies, due to the action of a field

Question 16

What are some examples of a non-contact force?

Answer 16

Gravitational force
Electrostatic force
Magnetic force

Question 17

What is Newton’s Third Law of Motion?

Answer 17

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

Question 18

What is Newton’s First Law of Motion?

Answer 18

If no resultant force acts, an object will remain stationary or move at a constant speed in the same direction

Question 19

What is Newton’s Second Law of Motion?

Answer 19

When a resultant force acts on an object, it produces an acceleration (or deceleration)

Question 20

What is magnitude?

Answer 20

Is the size or extent of something

Question 21

What is the resultant force if two unequal forces in opposite directions act on an object?

Answer 21

Equal to the difference between the two forces

In the direction of the larger force

Question 22

What are force pairs?

Answer 22

When a force is exerted on each object due to an interaction between two objects

Question 23

What is an example of a force pair?

Answer 23

The tension force exerted along a cable to a suspended object is opposed by the force of the weight of the object

Question 24

What is the centre of mass of an object?

Answer 24

The point through which the weight of an object acts

Question 25

How is the centre of mass of an irregular object found?

Answer 25

by locating its balance point

Question 26

What is the equation for weight?

Answer 26

w = mg

Question 27

What will happen in absence of air resistance?

Answer 27

all bodies near the Earth will fall with the same acceleration regardless of their mass

Question 28

What is resultant force?

Answer 28

Resultant force is a single force that describes all of the forces operating on a body

Question 29

What does the resultant force determine?

Answer 29

The direction in which the object will move as a result of all of the forces The magnitude of the final force experienced by the object

Question 30

What can forces combine to produce?

Answer 30

Balanced forces | Unbalanced forces

Question 31

What is a balanced force?

Answer 31

Balanced forces mean that the forces cancel each other out and no resultant force acts on the body

Question 32

What is an unbalanced force?

Answer 32

Unbalanced forces mean that the forces do not cancel out completely and there is a resultant force on the object

Question 33

What is the equation for resultant force?

Answer 33

f = ma

Question 34

What is tension?

Answer 34

The force experienced by a cable, rope, or string when pulled, hung, rotated or supported

Question 35

What is a normal contact force (reaction force)?

Answer 35

The force arising when an object rests against another object - that is acting at a 90° angle to the plane of contact

Question 35

What is upthrust?

Answer 35

The upward buoyancy force acting on an object when it is in a fluid

Question 36

What is friction?

Answer 36

The force that arises when two surfaces are in contact with each other

Question 37

What are free body diagrams used for?

Answer 37

to show the various forces acting on objects

Question 38

How do you find the energy stored for an elastic band on a graph?

Answer 38

calculate the area under the graph

Question 39

What is the parallelogram of forces used to find?

Answer 39

the resultant force of two forces that do not act along the same line

Question 40

How do you find the scale when finding the resolution of forces?

Answer 40

vector value / vector length (cm)

Question 41

How can an object be at equilibrium?

Answer 41

The resultant force on the object is zero | The forces acting on the object have no overall turning effect

Question 42

How can you determine if an object is at equilibrium?

Answer 42

if forces are parallel - the sum of force in one direction must be equal to the sum of force in another direction (resultant force is 0) if forces are perpendicular - the component on each line must balance out if the resultant force is 0

Question 43

equation linking force, spring constant and extension?

Answer 43

force (f) = spring constant (k) x extension (e)

Question 44

What makes an object elastic?

Answer 44

if it returns to its original shape when the forces deforming it have been removed

Question 45

When is the relationship linear between the extension of a spring and the force applied?

Answer 45

The extension of a spring is directly proportional to the force applied to it, as long as the limit of proportionality is not exceeded.

Question 46

When is the relationship non-linear between the extension of a spring and the force applied?

Answer 46

Beyond the limit of proportionality, the extension of a spring is no longer proportional to the force applied to it.

Question 47

What is Hooke's law?

Answer 47

fst

Question 48

equation for acceleration?

Answer 48

acceleration = change in velocity / change in time

Question 49

What are the factors affecting the centripetal force?

Answer 49

mass of the object its speed the radius of the circle