Forces and Motion - GCSE Flashcards

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1
Q

what is speed and velocity?

A

they are both how fast you’re moving

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2
Q

what are speed and velocity measured in?

A

m/s (or km/h or mph)

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3
Q

what is the difference between speed and velocity?

A

speed is how fast you are going with no regards of direction HOWEVER velocity must have a specified direction

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4
Q

what does the difference between speed and velocity mean?

just so you didn’t forget: speed is how fast you are going with no regards of direction HOWEVER velocity must have a specified direction

A

it means you can have objects travelling at a constant speed with a changing velocity

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5
Q

when does having an objects travelling at a constant speed with a changing velocity happen?

A

when the object is changing direction whilst staying at the same speed

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6
Q

what is the formula for average speed?

the formula which shows the relation between average speed, time, and distance

A

average speed = distance moved/ time taken

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7
Q

what is acceleration?

A

it is how quickly the velocity is changing

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8
Q

so acceleration is how quickly the velocity is changing,

but,

is it a change in speed or a change in direction?

A

it can be…

  • a change in speed
  • a change in direction
  • or a change in both
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9
Q

what is the unit of acceleration?

A

m/s (squared)

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10
Q

how many formulas are there for acceleration?

what are they?

A

2

fix this!!

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11
Q

what are the 9 units used in forces and motion?

A
  • kilogram (kg)
  • metre (m)
  • metre/seconds (m/s)
  • metre/seconds 2 (m/s 2)
  • newton (N)
  • seconds (s)
  • newton/kilograms (N/kg)
  • newton metre (Nm)
  • kilogram metre/ second (kg m/s)
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12
Q

where is the distance placed on a distance time graph?

A

on the y axis (usually in metres)

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13
Q

where is the time placed on a distance time graph?

A

on the x axis (usually in seconds).

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14
Q

what does it mean when the line in the distance time graph is flat?

A

it means the object is stationary.

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15
Q

what does the gradient of the line (change in y/ change in x) mean?

A

speed

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16
Q

Practical: how to investigating the motion of everyday objects such as toy cars or tennis balls?
(there are 8 points)

A
  • You need a stop watch and metre rule.
  • mark the start and end positions (to know the difference).
  • use a metre ruler to measure the distance.
  • put the toy car on the starting point and release it.
  • start the timer and stop it only when the car gets to the end point.
  • write down how long it took.
  • finally calculate the average speed by using the formula average speed = distance travelled/ time taken.
  • repeat experiment more than once.
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17
Q

what is the formula for acceleration?

A

acceleration = final velocity - starting velocity/ elapsed time

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18
Q

where does velocity go on a velocity time graph?

A

on the y axis (usually in m/s)

19
Q

where does time go on a velocity time graph?

A

on the x axis (usually in s)

20
Q

what does it mean when the line is flat on a velocity time graph?

A

it means the object is moving at a constant velocity.

21
Q

what is the gradient on a velocity time graph?

A

it is the acceleration.

22
Q

how do you calculate the distanced travelled on a velocity time graph?

A

you calculate the area under the line

23
Q

what formula do you use to calculate acceleration from the gradient of a velocity time graph?

A

gradient = acceleration = change in velocity/ time

24
Q

how to calculate the area under the graph?

A

It can be calculated as rectangles and triangles.

25
Q

what is the formula that calculates the relationship between final speed, initial speed acceleration and distanced moved?

A

(final speed) 2 = (initial speed) 2 + (2 x acceleration x distanced moved)

v2 = u2 + (2 x a x s)

key:
v = final speed
u = initial speed
a = acceleration 
s = distanced moved
(word2 = word squared)
26
Q

forces can act on a body to change what 3 things ?

A
  • velocity
  • speed
  • direction
27
Q

can forces act on the shape of a body?

A

yes, it can stretch it, squish it and twist it.

28
Q

what are the 9 different types of force?

A
  • gravitational
  • weight
  • friction
  • electrostatic
  • air resistance (drag)
  • tension (force in a spring)
  • up thrust
  • lift
  • thrust
29
Q

is force a vector?

A

yes, it has a direction, a push or pull, up, down, left or right.

30
Q

how to calculate a resultant force with lines that go to the same side?

A

you add them together.
e.g there are 2 arrows in the same side (right) of the car.

one is 30N the other is 60N.

the resulted force will be = 90N to the right

31
Q

how to calculate a resultant force with lines going the opposite side side?

A

you subtract the forces.
e.g there are town arrows, one in the right side and one in the left side of the car

the left side is 10N and the right side is 30N

you subtract them together (subtract the smaller force from the bigger force), meaning that the resultant force is = 20N to the right (because the right side has a bigger force)

32
Q

how is friction caused?

A

it is caused by rubbing surfaces.

33
Q

how does friction act?

A

it acts the opposite direction to motion.

34
Q

what is the formula for the relationship between unbalanced force, mass and acceleration?

A

force = mass x acceleration

f = m x a

35
Q

what is the formula for the stopping distance?

A

stopping distance = thinking distance + breaking distance

36
Q

what is the formula for the relationship between weight, mass and gravitational field strength?

A

weight = mass x gravitational field strength

W = m x g

37
Q

what factors affect Thinking distance?

there are 4

A
  • tiredness
  • alcohol
  • speed of the car
  • drugs
38
Q

what factors affect Braking distance?

there are 5

A
  • road conditions
  • tyre conditions
  • brake conditions
  • speed of the car
  • mass of the car
39
Q

what are the forces acting on falling objects? explain what happens when an object falls
(there are 4 point you need to make)

A
  • as the object gains speed, the object’s weight stays the same however, the air resistance increases.
  • there is a resultant force acting downwards.
  • Eventually the object’s weight will be balanced by air resistance.
  • there is no resultant force and the object reaches a steady speed (this is known as thermal velocity).
40
Q

practical/ investigate: how does extension varies with applied force for helical springs, metal wires and rubber bands.
(there are 6 points)

A
  1. measure the length of your spring (without any hanging masses).
  2. hang a mass of 100g on the spring.
  3. measure the new length of the spring.
  4. calculate the extension of the spring.
  5. continue increasing the mass, calculating the new length of the spring, and calculating the extension of the spring.
  6. take note of your results and put it on a table.
41
Q

what is Hooke’s law?

A

Hooke’s law states for small deformation of and object, the displacement or size of the deformation is directly proportional to the deforming force or load.

42
Q

what is elastic behaviour?

A

it is the ability of a material to recover original shape after the force is removed.

In a spring it occurs when the force is lower than the elastic limit.

43
Q

what is elapsed time ?

A

is the amount of time that passes from the start of an event to its finish