Forces

Question 1

what is the equation for speed?

Answer 1

v = s / t

Question 2

how do you find the distance on a velocity time graph?

Answer 2

distance is the area under the graph

Question 3

what are the units for accelaration?

Answer 3

m/s ^2

Question 4

when do you use the equation v^2= u^2+2AS

Answer 4

for any question that uses constant accelaration

Question 5

what is stopping, thinking and braking distance?

Answer 5

stopping distance is the distance needed for a car to stop at a given speed

thinking distance is the distance we travel in the time it takes for us to react to the situation

braking distance the distance travelled after you start braking

Question 6

what are some factors affecting thinking distance?

Answer 6

tiredness
distractions
alcohol
old age
drugs

Question 7

what are some factors affecting braking distance?

Answer 7

bad condtions of the brakes
greater speed
mass of the vechicle
bad condition of the vechicle
icy/wet roads

Question 8

what happens during braking?

Answer 8

brakes apply a force to the wheels and then the brakes use frictional forces
brake discs and shoe heat up
the vechicle comes to a stop

Question 9

what are some contact and non-contact forces?

Answer 9

contact-
friction
air resistance
tension

gravity
electrostatic force
magnetic force

Question 10

what is a vector quantity?

give some examples

Answer 10

a vector quantity is a quantity that has both magnitude and direction

velocity
force displacement
accelaration

Question 11

what is a scalar quantity?

give some examples

Answer 11

a scalar quantity is a quantity that tells you only magnitude

distance
speed
length
mass

Question 12

how do you draw a vector diagram?

Answer 12

arrow pointing in the correct direction at correct angle with scale clearly written

Question 13

what is a resultant force?

Answer 13

the overall effect of more than one force

Question 14

how do you represent resultant forces graphically?

Answer 14

draw your vectors and connect ends of both arrows to form a rectangle
draw an arrow to the corner and measure and label your angles
measure resultant force using the convert scale

Question 15

what is newtons first law of motion?

Answer 15

on object in motion stays in motion at a constant velocity and straight line unless acted on by an unbalanced force

Question 16

what is inertia?

Answer 16

the tendency of an object to resist changes in their state of motion

Question 17

how does mass effect inertia?

Answer 17

an object with a larger mass is has a greater tendency to resist changes in its state of motion

Question 18

what is newtons second law of motion?

Answer 18

the accelaration of an object is directly proportional to the force applied to it and inversely proportional to its mass

Question 19

what is mass measure in?

Answer 19

kg

Question 20

what is newtons third law?

Answer 20

for every action there is an opposite and equal reaction

Question 21

how are mass and weight different?

Answer 21

mass never changes, you have the same mass anywhere in the universe
weight does change depending on the strength of the gravitational field strength acting on your mass

Question 22

what comnditions are needed for terminal velocity?

Answer 22

balanced forces
zero accelaration
constant velocity

Question 23

if a skydiver jumps out of a plane why does the upward force increase as he falls?

Answer 23

becuase air resistane is directly proportional to the velocity and as he is falling gravity is pulling him closer so his speed increase meaning air resistance does as well

Question 24

what is directly proportional to velocity when an object falls?

Answer 24

air resistance

Question 25

what is terminal velocity?

Answer 25

when an object moves with zero accelaration and constant velocity this means the forces are also balanced

Question 26

what are the units for extension?

Answer 26

metres

Question 27

what are the units for the spring constant?

Answer 27

n/m

Question 28

what does it mean if something is elasticly deformed?

Answer 28

the object will return back to its normal shape

Question 29

what do we see if an object does not return back to its normal shape?

Answer 29

it has been deformed

Question 31

what is inelastic deformation?

Answer 31

when the object does not return back to its normal shape

Question 32

what is the limit of proportionality?

Answer 32

where inelastic deformation happens and it starts to disobey hookes law

Question 33

what is hooke's law?

Answer 33

the extension of a spring is in direct proportion with the load added as long as the load does not exceed the elastic limit

Question 34

what is a moment?

Answer 34

the turning effect of a force around a pivot

Question 35

what does the size of a moment depend on?

Answer 35

the force (weight) acting the perpendicular distance from the pivot

Question 36

what makes something more stable?

Answer 36

being closer to the ground and having a wider base

Question 37

what are gears?

Answer 37

rotating wheels with teeth that interlock used to transmit or multiply rotational forces

Question 38

what does a low gear do?

Answer 38

gives a low speed but a high turning effect

Question 39

how can you find the centre of mass of a material?

Answer 39

suspend the material freely from a stand attach plumbline and draw the line of action of mass rotate the material and suspend again this time from a different point once again use the plumbline to draw the line of action of mass where the two lines meet is where the centre of mass is

Question 40

what is work done also known as?

Answer 40

energy transfered

Question 41

what are the units for work done/energy transfered?

Answer 41

Joules

Question 42

What are some times where we can tell no work has been done?

Answer 42

when a force is exerted but the object dosent move when an object is carried at a constant velocity by a force perpendicular to the motion no work is done

Question 43

what is 1 watt equal to in terms of energy transfered?

Answer 43

1 joule of energy per second

Question 44

what are the units for momentum?

Answer 44

kgm/s

Question 45

what is the law of conservation of momentum?

Answer 45

momentum before = momentum after as long as no external forces are acting

Question 46

how is the momentum changes in a front end and rear end impact?

Answer 46

in a front end impact the momentum is reduced reduced in a rear end impact the momentum of the car is increased