physics

Question 1

average speed =

Answer 1

distance moved / time taken

Question 2

acceleration =

Answer 2

change in velocity / time taken

Question 3

force =

Answer 3

mass x acceleration

Question 4

weight =

Answer 4

mass x g

Question 5

momentum =

Answer 5

mass x velocity

Question 6

moment =

Answer 6

change in momentum / time taken

Question 7

Q(charge) =

Answer 7

I x t (current x time)

Question 8

E (energy) =

Answer 8

Q x V (current x voltage)

Question 9

V (voltage) =

Answer 9

I x R (current x resistance)

Question 10

P (power) =

Answer 10

I x V (current x voltage)

Question 11

wave speed =

Answer 11

frequency x wavelength

Question 12

n (refractive index) =

Answer 12

sin i / sin r

Question 13

sin c (sin of critical angle) =

Answer 13

1 / n (refractive index)

Question 14

Effeciency =

Answer 14

useful energy output / tutal energy output

Question 15

what does it mean if the line is steep on a distance time graph

Answer 15

the greater the steepness the greater the speed of the object

Question 16

examples of forces

Answer 16

weight
lift
electrostatic
tension
friction
thrust
magnestic
drag
contact
upthrust

Question 17

what is a resultant force (and how do you calculate it)

Answer 17

if more than one force acts on an object you have to calculate the resultant force
(bigger force - smaller force = resultant force)
AND SAY THE DIRECTION

Question 18

what happens if the resulant force is in the same direction as the object

Answer 18

the object will accelerate

Question 19

what happens if the resultant force is in the opposite direction to the object

Answer 19

the object will decelerate

Question 20

what happens if the resultant force is zero

Answer 20

the object will be stationary or moving at a contant speed

Question 21

what is terminal velocity

Answer 21

The maximum speed of an object, reached when the forces moving the object are balanced by its frictional forces.

Question 22

what is a scalar

Answer 22

a quantity that just has a size

Question 23

what is a vector

Answer 23

a quantity which has size and direction

Question 24

How can we tell Hooke’s law on a graph

Answer 24

on a force extension graph is the line is straight through 0 then the object is obeying the law

Question 25

what does it mean if an object has elasticity

Answer 25

the object returns to its original shape after the force is removed

Question 26

which part of a velocity time graph can be used to calculate distance travvled

Answer 26

the area under the graph

Question 27

what are ways that force can affect the object that it is being applied on

Answer 27

change in shape change in speed change in direction

Question 28

what is the equation between stopping distance breaking distance thinking distance of a car while it is stopping

Answer 28

stopping distance = thinking distance + breaking distance

Question 29

what is the thinking distance

Answer 29

the distance the vehicle travels in the time it takes for th driver to apply the breaks after realising they need to stop

Question 30

what are things that affect thinking distance

Answer 30

drugs, alcohol, distractions and tiredness

Question 31

what is breaking distnace

Answer 31

the distance that an object travels from the time when the breaks are applied to the time when it comes to a complete stop

Question 32

what factors affect breaking distance

Answer 32

speed of the vehicle, road conditions, weight of the vehicle, and slippery roads

Question 33

what are safety features in roads

Answer 33

roundabouts narrow lanes speed bumps traffic lights stop signs speed limits

Question 34

what are safety features in cars

Answer 34

airbags seatbelts cruise control headlights breaklights parking sound assists

Question 35

what are many injuries in vehicle collisions and sporting injuries due to

Answer 35

the rapid acceleration of the body (they stop very quickly)

Question 36

what can you do to the momentum to help improve the injury

Answer 36

by spreading the change in momentum over a longer time it recudes the force required to act which reduces the injury

Question 37

explain how the seatbelt protects

Answer 37

it stretches so it increases the time to come to a stop

Question 38

explain how a crumple zone protects

Answer 38

parts of the car are desgined to collapse so the car takes longer to stop moving

Question 39

what is the conservation of momentum

Answer 39

total momentum before = total momentum after

Question 40

what is newtons 3rd law

Answer 40

when objects are touching they exert equal and opposite forces on eachother

Question 41

what is a lever

Answer 41

an object rotating or trying to rotate

Question 42

what is a pivot

Answer 42

the point around which the lever is rotating or trying to rotate

Question 43

what is a moment

Answer 43

the size of the turning effect of a force about a pivot

Question 44

what is the principle of moments

Answer 44

clockwise moment = anticlockwise moment

Question 45

what is the centre of gravity

Answer 45

the point in an object where all of the wright appears to act

Question 46

how do you find the centre of gravity

Answer 46

if an object is placed such that it's centre of gracity is on top of a pivot, the object will be balanced

Question 47

why will the object be balanced when you find its centre of gravity

Answer 47

the perpendicular distance between theweight of the object and the pivot will be zero