Forces

Question 1

What do scalar quantities have?

Answer 1

MAGNITUDE (size) only. DO NOT have a DIRECTION.

Question 2

Give 3 examples of scalar quantities.

Answer 2

Any 3 from: mass, temperature, speed, energy, distance and time

Question 3

What do vector quantities have?

Answer 3

MAGNITUDE and DIRECTION.

Question 4

Give 3 examples of vector quantities.

Answer 4

Any 3 from: displacement, weight, force, velocity, acceleration and momentum.

Question 5

What two categories can forces be divided into?

Answer 5

Contact forces and non-contact forces.

Question 6

What is a force?

Answer 6

A force is a PUSH or a PULL that acts on an object due to the INTERACTION with another object.

Question 7

What is a contact force?

Answer 7

A contact force where TWO OBJECTS are PHYSICALLY TOUCHING.

Question 8

Give an example of a contact force.

Answer 8

Any 1 from: friction, tension and air resistance.

Question 9

What is a non-contact force?

Answer 9

Where to the TWO OBJECTS are PHYSICALLY SEPARATED.

Question 10

Give an example of a non-contact force.

Answer 10

Any 1 from: gravitational force, electrostatic force and magnetic force.

Question 11

What is meant by mass?

Answer 11

The mass of an object tells us how much MATTER the object has IN IT.

Question 12

What is meant by weight?

Answer 12

The weight of an object is the FORCE acting on it due to GRAVITY.

Question 13

What equation do you use to calculate weight?

Answer 13

weight (N) = mass (kg) x gravitational field strength (N/kg) W = m g

Question 14

What can we say about weight and mass of an object?

Answer 14

The weight of an object is DIRECTLY PROPORTIONAL to the mass of the object. Weight ∝ Mass

Question 15

What is meant by gravitational field strength?

Answer 15

It is a measure of the force of GRAVITY in a particular LOCATION.

Question 16

What is meant by altitude?

Answer 16

HEIGHT above the ground.

Question 17

What is key about inelastic material?

Answer 17

They DO NOT return to their original length when the forces are removed (INELASTIC DEFORMATION).

Question 18

What equation do we use to calculate the force needed to stretch an elastic object?

Answer 18

Force (N) = spring constant (N/m) x extension (m)

Question 19

What equation do we use to calculate speed?

Answer 19

speed (m/s) = distance / time

Question 20

What does the gradient of a distance time graph tell us?

Answer 20

Tells us the object’s SPEED.

Question 21

How do you work out the gradient?

Answer 21

gradient = distance travelled / time taken

Question 22

What equation do we use to calculate acceleration?

Answer 22

………………………….2

acceleration (m/s) = change in velocity (m/s) / time (s)

Question 23

What does the gradient of a velocity time graph tell us?

Answer 23

The ACCELERATION of the object.

Question 24

What does a horizontal line show us?

Answer 24

That the object is travelling at a CONSTANT VELOCITY.

Question 25

What does an upward sloping line tell us?

Answer 25

That the object is ACCELERATING.

Question 26

What does a downward sloping line tell us?

Answer 26

That the object is DECELERATING.

Question 27

What does the total area under the graph tell us?

Answer 27

The DISTANCE TRAVELLED in a specific direction (displacement).

Question 28

What is key about Newton's First Law of Motion in relation to resultant force?

Answer 28

The VELOCITY of an abject will only change if a RESULTANT FORCE is acting on the object.

Question 29

What is Newton's second law of motion?

Answer 29

The ACCELERATION of an object is PROPORTIONAL to the RESULTANT FORCE acting on the object and INVERSELY PROPORTIONAL to the MASS of the object.

Question 30

What is Newton's third law of motion?

Answer 30

Whenever two objects interact, the FORCES they exert on each other are EQUAL and OPPOSITE.

Question 31

What is meant by the stopping distance?

Answer 31

Is the total DISTANCE travelled from when the driver first spots the obstruction to when the car stops.

Question 32

What is meant by the thinking distance?

Answer 32

The distance travelled by the car during the driver's REACTION TIME.

Question 33

What is meant by the reaction time?

Answer 33

The time taken for the driver to spot the obstruction, make a decision and then move their foot to the brake.

Question 34

What is meant by the breaking distance?

Answer 34

It is the distance the car travels from when the driver APPLIES THE BRAKES to when the car STOPS.

Question 35

What is the stopping distance made up of?

Answer 35

The THINKING DISTANCE plus the BRAKING DISTANCE.

Question 36

What happens when we double the velocity of the car?

Answer 36

The KINETIC ENERGY QUADRUPLES.

Question 37

What momentum do non moving objects have?

Answer 37

NO MOMENTUM.

Question 38

What equation do we use to calculate momentum?

Answer 38

momentum (kg m/s) = mass (kg) x velocity (m/s)

Question 39

What is the conservation of momentum?

Answer 39

In a closed system, the total momentum BEFORE an event is equal to the total momentum AFTER an event.

Question 40

What does unifrom mean?

Answer 40

When ab object's speed (velocity) is increasing at a **constant rate**.

Question 41

Label the following on a distance-time graph: Steady speed, stopped, accelerating and decelerating.

Answer 41

Question 42

What does the gradient equal on a distance-time graph?

Answer 42

Gradient = **speed** (The steeper the graph, the faster the object is going.) This is because: speed = distance / time = (change in vertical axis) / (change in horizontal axis).

Question 43

Label the following on a velocity-time graph: constant acceleration, steady speed, increasing acceleration, steady speed and constant deceleraion.

Answer 43

Question 44

What does the gradient equal on a velocity-time graph?

Answer 44

Gradient = **acceleraion**, since acceleration is **change in velocity / time**.