Year 9 term 1

Question 1

State Newton’s 3rd law of motion

Answer 1

• “When you push something it pushes you back just as hard, but in the opposite direction”
• “for every action there is an equal opposite force”

Question 2

State the formula of momentum

Answer 2

p=mv

Question 3

State the formula linking force, change in momentum, and time

Answer 3

F=(mv-mu)/t

Question 4

2 things drag force depends on

Answer 4

• shape
• speed

Question 5

Define drag coefficient

Answer 5

How easily an object can move through air

Question 6

Define terminal velocity

Answer 6

steady speed achieved by an object freely falling through a gas or liquid.

Question 7

Define momentum

Answer 7

A measure of how hard it is to stop a moving object

Question 8

The law of momentum in collisions

Answer 8

Momentum before collision=momentum after collision

*the momentum has just been conserved, one object gains the momentum the other object lost

Question 9

How do crumple zones improve survival rate?

Answer 9

In a crash, the victim dies because of the exceeding force on them. The crumple zones decrease time, increase deceleration hence in the formula; F=ma, the deceleration decreases the force overall, hence improving survival rate.

Question 10

Newtons 3rd law and momentum displayed on a rocket taking off

Answer 10

• Every force has an opposite reaction; rockets fuel falling down, rocket goes up
• momentum; velocity of feul being exhuased downwards meaning the rockets velocity increases as it goes upwards, p=mv, velocity increasing meaning momentum increases.

Question 11

Formula for speed

Answer 11

Speed=distance/time

Question 12

Formula for velocity

Answer 12

velocity=displacement/time

Question 13

Formula of acceleration

Answer 13

a=(v-u)/t

Question 14

stopping distance=…

Answer 14

thinking distance+breaking distance

Question 15

Define thinking distance

Answer 15

The driver will have a reaction time to the object on the road, this reaction time between him seeing the object and pressing the breaks is the

Question 16

Factors affecting thinking distance

Answer 16

• age
• tiredness
• loudness
• alchohol
• speed of car

Question 17

Factors affecting stopping distance

Answer 17

• weather
• speed of car

Question 18

define stopping distance

Answer 18

distance crossed between driver pressing breaks and the car stopping

Question 19

in a velocity-time graph, where can i find the distance?

Answer 19

under the line

Question 20

Outline an experiment to measure the speed of cars

Answer 20

• using a click measure, measure 50 m distance between you and your partner
• Start a timer when your friend signals a car has passed the first point
• Stop the timer once car passes
• Use s=d/t to find the speed

*this experiment is heavily based on reaction time; hence it may not be accurate.

Question 21

What do I multiply m/s with to convert it to km/h

Answer 21

x3.6

Question 22

In a distance-time graph, what is the gradient?

Answer 22

speed

Question 23

WHta is the gradient of a velocity-time graph representing?

Answer 23

acceleration

Question 24

If both forces sum up to zero, what will happen?

Answer 24

Nothing

Question 25

Difference of drag and upthrust

Answer 25

Drag is in air, upthrust is focused on gravity

Question 26

How will an increase in friction benefit cars

Answer 26

Better tyres and breaks

Question 27

How would a decrease in friction benefit cars?

Answer 27

Better efficiency(less energy needed), faster materials

Question 28

Everything can ----- to become long and ----- to become short, however in some its easier to observe other factors such as ----- in -----

Answer 28

1. Strech 2. compress 3. Brittlness 4. glass

Question 29

State Hooke's law

Answer 29

"Springs change shape when a force is applied, and return once force is removed

Question 30

Ëxtension of springs is Proportional to -----

Answer 30

Force

Question 31

Define the limit of propertionality

Answer 31

the spring starts bending/extension starts excelerating

Question 32

Defien elastic limit of springs

Answer 32

After this point, the spring will not return to its normal shape even after the force is removed

Question 33

limit of proportionality and elastic limit also apply to ----, however if it streches ----ly it will return to it's original shape, if it streches ------ly it will not do this.

Answer 33

- wires - Elastically - Plastically

Question 34

Formula of weight

Answer 34

W=mg

Question 35

Formula of force

Answer 35

F =ma

Question 36

formula of force with momentum

Answer 36

F= delta p/ delta t ## Footnote *as t increases f decreases

Question 37

# newtons 3rd law paired forces must be...

Answer 37

- same size - opposite direction(negative quantities) - same type - 2 different objects

Question 38

newtons second law

Answer 38

object will accelerate in the direction of a force

Question 39

newtons first law

Answer 39

object at stationary has equal forces so stationary until force of push or pull acts on it ## Footnote equilibrium object=forces on object equal

Question 40

moment formula

Answer 40

=forcexperpendicular distance

Question 41

weigth of a body acts through....

Answer 41

its centre of gravity