Section 1 - Motion, Forces and Conservation of Energy

Question 1

What are vectors?

Answer 1

Quantities with both magnitude and direction.

Question 2

What are scalars?

Answer 2

Quantities with magnitude only.

Question 3

What are some examples of vector quantities?

Answer 3

Force, velocity, displacement, weight, acceleration and momentum.

Question 4

What are some examples of scalar quantities?

Answer 4

Speed, distance, mass, energy, temperature and time.

Question 5

What is a distance, in physics, defined as?

Answer 5

How far an object has moved.

Question 6

What is displacement, in physics, defined as?

Answer 6

The distance and direction in a straight line from an object’s starting point to it’s finishing point.

Question 7

What is speed, in physics, defined as?

Answer 7

Speed is a measure of how fast something is going.

Question 8

What is velocity, in physics, defined as?

Answer 8

How fast something is going and in what direction.

Question 9

Describe the formula relating (average) speed & time.

Answer 9

d=s×t

d = distance
s = (average) speed
t = time

Question 10

What is acceleration, in physics, defined as?

Answer 10

The change in velocity over a certain amount of time.

Question 11

What is uniform acceleration, in physics, defined as?

Answer 11

Speeding up (or slowing down) at a constant rate.

Question 12

Describe the formula relating acceleration, time and change in velocity.

Answer 12

a=(v-u)/t

a = acceleration
v = final velocity
u = initial velocity
t = time

Question 13

Describe the formula for constant acceleration.

Answer 13

v²-u²=2×a×x

v = final velocity
u = initial velocity
a = acceleration
x = distance

Question 14

Which graph shows how far something has traveled?

Answer 14

Distance/Time graphs.

Question 15

Which graph can have both positive and negative gradients?

Answer 15

Velocity/Time graphs.

Question 16

In a distance/time graph, how can speed be worked out?

Answer 16

Speed = gradient = change in y / change in x

Question 17

In a velocity/time graph, how is distance worked out?

Answer 17

By calculating the area under the graph.

Question 18

What is Isaac Newton’s first law?

Answer 18

Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.
Or a still object will not move unless forced to, and a moving object will not stop or change direction unless forced to.

Question 19

Describe the equation relating resultant force and acceleration.

Answer 19

F=m×a

F = resultant force
m = mass
a = acceleration

Question 20

List some safety features used in cars.

Answer 20

Seat belts, air bags and crumple zones.

Question 21

What is mass, in physics, defined as?

Answer 21

The amount of ‘stuff’ in an object.

Question 22

What is weight, in physics, defined as?

Answer 22

Mass with gravity.

Question 23

Describe the equation for weight.

Answer 23

W=m×g

W = weight
m = mass
g = gravitational field strength

Question 24

What is Isaac Newton’s second law?

Answer 24

Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration.

Question 25

What is inertia?

Answer 25

Inertia is the tendency for motion to remain unchanged.

Question 26

What is Isaac Newton's third law?

Answer 26

For every action, there is an equal and opposite reaction.

Question 27

What is momentum, in physics, defined as?

Answer 27

The property that all moving objects have.

Question 28

Describe the equation for momentum.

Answer 28

p=m×v ``` p = momentum m = mass v = velocity ```

Question 29

How, in a closed system, is momentum affected after an event. What is it called.

Answer 29

It isn't, momentum before an event is equal to the momentum after the event. This is known as conservation of momentum.

Question 30

Describe the equation relating force and change in momentum.

Answer 30

F=(mv-mu)/t ``` F = force m = mass v = final velocity u = initial velocity t = time ```

Question 31

List the types of Energy Store.

Answer 31

``` Kinetic Thermal Chemical Gravitational Potential Elastic Potential Electrostatic Magnetic Nuclear ```

Question 32

Describe the equation for working out the work done by a vehicle's brakes.

Answer 32

1/2×m×v²=F×d ``` m = vehicle's mass v = velocity F = braking force d = braking distance ```

Question 33

Describe the equation for kinetic energy.

Answer 33

KE=1/2×m×v² ``` KE = Kinetic Energy m = mass v = velocity ```

Question 34

What is Kinetic Energy?

Answer 34

Energy which a body possesses by virtue of being in motion.

Question 35

Describe the equation for a change in Gravitational Potential Energy.

Answer 35

ΔGPE=m×g×Δh ``` ΔGPE = change in Gravitational Potential Energy m = mass g = gravitational field strength Δh = change in height ```

Question 36

What is Gravitational Potential Energy?

Answer 36

Gravitational Potential Energy is energy an object possesses because of its position in a gravitational field.

Question 37

What is Conservation of Energy?

Answer 37

The fact that energy can neither be created or destroyed.

Question 38

List the four main methods of energy transfer.

Answer 38

Mechanically Electrically By heating By Radiation

Question 39

How is energy made useful?

Answer 39

By transferring it into a useful store.

Question 40

Describe the equation for efficiency.

Answer 40

Ef=(Eu÷Et)×100 Ef = Efficiency Eu = Useful energy Et= Total energy

Question 41

How can efficiency be increased?

Answer 41

By removing unwanted energy transfers.

Question 42

How can unwanted energy transfers such as friction and heating be removed?

Answer 42

Lubrication reduces energy transfer by friction. Insulation reduces energy transfer by heating.

Question 43

List the types of energy sources. Are they renewable or non-renewable? polluting or non-polluting?

Answer 43

``` Fossil fuels, non-renewable, polluting Nuclear, non-renewable, polluting Bio-fuels, renewable, polluting Wind, renewable, non-polluting The sun, renewable, non-polluting Hydro-electric, renewable, non-polluting Tides, renewable, non-polluting ```

Question 44

What are current trends in Energy Resource use?

Answer 44

Currently we depend on fossil fuels, followed closely by nuclear fuels. However, we are slowly drifting towards renewable, non-polluting fuels like wind and solar.

Question 45

What percentage of the total energy produced in the UK produced using renewable resources?

Answer 45

15%

Question 46

What is limiting the current efforts to shift to renewable energy sources?

Answer 46

Cost, reliability, aesthetics, research, personal changes.