Assessment 2: P8-P11

Question 1

What is a fluid

Answer 1

A substance that can flow (liquids and gases)

Question 2

Describe upthrust

Answer 2

It is a force that pushes things upwards

Question 3

Describe the difference between vector and scalar quantities

Answer 3

Vector quantities have a size and direction whereas scalar quantities only have a size

Question 4

Give an example of a scalar and a vector quantity

Answer 4

Scalar: energy
Vector: displacement

Question 5

What do the length and direction of arrows represent for forces

Answer 5

Their length represent the magnitude of the force, while their arrowheads represent the direction where the force acts.

Question 6

List the different types of forces, e.g. friction.

Answer 6

Air resistance
Drag
Water resistance
Magnetism
Gravity
Elastic
Electrostatic

Question 7

What is the equation that links weight, mass and gravitational field strength

Answer 7

𝑊 = 𝑚 𝑔

Question 8

definition for a resultant force

Answer 8

the total amount of force acting on the object or body along with the direction of the body.

Question 9

Describe the relationship between mass and weight

Answer 9

Weight is the measure of the force of gravity on an object’s mass, while mass is the measure of how much matter there is in an object. The proportionality between weight and mass lead to the following relationship: W = m x g. W: Weight (in newton) m: mass (in kilogram)

Question 10

Where does the weight act for an object?

Answer 10

The objects center of mass

Question 11

Give some examples of balanced and m unbalanced forces.

Answer 11

Balanced force examples: A car that continues movies at the same speed, an object floating on water, a person standing still.

Unbalanced force examples: A vehicle accelerating, a fruit falling from a tree, a moving train slowing down before stopping.

Question 12

What is the equation linking work done, distance and force?

Answer 12

Work = Force × Distance

Question 13

What is the difference between displacement and distance?

Answer 13

Distance is the length of the path taken by an object whereas displacement is simply the distance between where the object started and where it ended up.

Question 14

Write the units and symbols for the following:
work done:
force:
distance:

Answer 14

Work done: Joules= J
Force : Newtons=N
Distance : metres= m

Question 15

How much work is done on a stationary box that is moved across a carpet by a person? The box weighs 5N and it is moved 50cm

Answer 15

Force= 5N
Displacement= 50cm (convert to metres) =0.5m

Work done = Force x displacement/distance
Work done = 5 x 0.5
Work done = 2.5 J

Question 16

How many forces are required to stretch an elastic band and why?

Answer 16

1.two forces are involved, acting inwards onto the object; we call these forces “compression forces”.

2. Stretching a blob of blu-tac or a rubber band: two forces are involved, acting outwards from the object; we call these forces “tension forces”.

Question 17

Describe the difference between elastic deformation and inelastic deformation.

Answer 17

When an object is deformed, (stretched, bent or compressed), if it returns to its original shape once the forces are removed, it is an elastic deformation. If it does not return to its original shape it is an inelastic deformation.

Question 18

Describe the relationship between extension of an elastic object and force applied.

Answer 18

extension of an elastic object is directly proportional to the force applied to it. In other words: • If the force applied is doubled, the extension doubles • If no force is applied, there is no extension The graph of force against extension is a straight line through the origin, which shows a linear relationship.

Question 19

What is the equation that links force, spring constant a and extension?

Answer 19

As an equation, Hooke’s Law can be represented as F = kx, where F is the force we apply, k is the spring constant, and x is the extension of the material (typically in meters)

Question 20

Write the units and symbols for the following:
force:
spring constant:
extension:

Answer 20

force (F) is measured in newtons (N)
spring constant (k) is measured in newtons per metre (N/m)
extension (e), or increase in length, is measured in metres (m)

Question 21

What is spring constant

Answer 21

It is a measure of the stiffness of the spring

Question 22

describe the difference between a linear and non linear relationship for force and extension

Answer 22

Hooke’s law is used to describe the relationship between force applied to an elastic object and the extension of the elastic object. It is a linear relationship, where force is directly proportional to the extension. If an object doesn’t obey Hooke’s law, there is a non-linear relationship between force and extension.

Question 23

When an object is balanced, what is the relationship between the clockwise and anticlockwise moments?

Answer 23

If an object is balanced, the total clockwise moment about a point is equal to the total anticlockwise moment about the same point. This is called the Principle of Moments. Total clockwise moment = Total anticlockwise moment.

Question 24

Would a long or a short spanner be more effective to loosen a nut?

Answer 24

A long spanner

Question 25

What is the equation that links pressure, force normal to a surface and area of that surface?

Answer 25

P = F A

Question 26

What is the cause of pressure in fluids

Answer 26

The pressure in a liquid is due to the weight. The force acts towards the centre of the planet and is measured in newtons (N). of the column of water above. Since the particles in a liquid are tightly packed, this pressure acts in all directions.

Question 27

What is the equation linking pressure, height of the column, density of the liquid and gravitational field strength?

Answer 27

Pressure due to the weight of a liquid of constant density is given by p=ρgh p = ρ g h , where p is the pressure, h is the depth of the liquid, ρ is the density of the liquid, and g is the acceleration due to gravity

Question 28

What factors affect pressure in a column at a particular point?

Answer 28

The pressure at a point in a liquid depends on:
density of the liquid.
acceleration due to gravity.
depth below the free surface

Question 29

The pressure at a point in a liquid depends on:
density of the liquid.
acceleration due to gravity.
depth below the free surface.
Explain why these factors affect the pressure

Answer 29

Density of the liquid affects pressure because when density increases pressure also increases- directly proportional to one another

Acceleration due to gravity affects pressure because Gravity’s influence on fluid pressure is that it causes the fluid body to move in the opposite direction of its net acceleration.

Depth below the free surface affects pressure because the deeper the object is placed in the fluid, the more pressure it experiences. This is because is the weight of the fluid above it. The more dense the fluid above it, the more pressure is exerted on the object that is submerged, due to the weight of the fluid.

Question 30

explain which factors influence whether an object floats or sinks

Answer 30

Density is a measure of how heavy something is compared to its size. If an object is more dense than water it will sink when placed in water, and if it is less dense than water it will float.

Question 31

what is atmospheric pressure

Answer 31

Air molecules colliding with a surface cause atmospheric pressure. Atmospheric pressure at sea level is about 101,000 Pa (101 kPa) but just 27,000 Pa (27 kPa) at the cruising altitude of a passenger plane. Atmospheric pressure decreases as the height of a surface above ground level increases.

Question 32

why does atmospheric pressure vary with height above a surface

Answer 32

pressure decreases with increasing altitude. This is because as the altitude above the surface increases there are fewer air molecules therefore the mass decreases - decreasing the pressure

Question 33

what factors will affect the speed a person can walk

Answer 33

the force acting on the object, the mass of the object, the surface it is moving on, and the presence of friction or other resistive forces.

Question 34

what is the equation linking distance travelled, speed and time

Answer 34

Speed = distance/time

Question 35

what is the difference between speed and velocity

Answer 35

Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object’s movement. Put another way, speed is a scalar value, while velocity is a vector

Question 36

describe what happens to the velocity of an object moving in a circle at a constant speed

Answer 36

An object moving in a circular orbit at a constant speed has a changing velocity

Question 37

What does a distance time graph represent

Answer 37

A distance-time graph shows how the distance and speed of an object changes with time.

Question 38

How can you find the speed from a distance time graph

Answer 38

In a distance-time graph, the gradient of the line is equal to the speed of the object. The greater the gradient (and the steeper the line) the faster the object is moving.

Question 39

How can you tell if an object is moving at a faster speed in a distance time graph

Answer 39

The steeper the line (and the greater the gradient) the faster the object is moving.

Question 40

what is the equation linking acceleration change in velocity and time

Answer 40

a = v/t

Question 41

what is the equation for uniform acceleration

Answer 41

v=u + at

Question 42

Units for acceleration, initial velocity and final velocity

Answer 42

final velocity (v) is measured in metres per second (m/s) initial velocity (u) is measured in metres per second (m/s) acceleration (a) is measured in metres per second squared (m/s2)