Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AQA Physics > Forces > Flashcards

Forces Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

what are scalars and vectors?

A
  • scalars have magnitude only
  • vectors have a magnitude and a given direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how can vectors be represented?

A

with an arrow
- length of arrow= size of vector
- direction of arrow=direction of vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are contact and non-contact forces?

A
  • a push or pull that acts on an object due to the interaction with another object
  • contact forces – objects are touching eg. friction, air resistance,
  • non-contact forces – objects are separated eg. gravitational force, electrostatic force, magnetism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is weight?

A

force of gravity acting on an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

weight equation

A

W=mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what’s the centre of mass?

A

the single point where weight acts on an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is resultant force?

A

one force that has the same effect as all forces acting on an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

work done equation

A

W=Fs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens to an object temp is friction acts on it?

A

temp will rise as work is done against friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

force (elastic) equation

A

F=ke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the relationship between extension and force?

A

directly proportional until limit of proportionality isn’t exceeded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is moment?

A

the turning effect of a force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

moment equation

A

M=Fd
d is the perpendicular distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what happens to the moments if an object is balanced?

A

total clockwise moment equals total anti-clockwise moment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what makes up a lever system?

A
  • load
  • effort
  • pivot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how can a lever be used as a force multiplier?

A

distance between pivot and effort = greater than distance between pivot and load=force applied on load greater than effort force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what affects the moment of a gear?

A

its size
larger gear=slower+larger moment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is a fluid?

A

a liquid or a gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

pressure equation

A

p=F/A

20
Q

pressure on column of liquid equation

A

p=hpg

21
Q

where do objects experience more pressure?

A

at the bottom of a column=resultant force up=upthrust

22
Q

what influences whether an object floats or sinks?

A
  • An object floats when its weight is equal to or less than the upthrust.
  • An object sinks when its weight is greater than the upthrust
  • The water level in a water container rises when an object is lowered into water given that the object displaces some water:
    -the more the object is lowered into the water, the bigger volume that is displaced, causing a larger up thrust
    -When an object is completely immersed in water, the weight of water displaced is equal to the force of up thrust acting on the object
  • A partially (or totally) submerged object experiences a greater pressure on the bottom surface than on the top surface as pressure is proportional to the depth of the object
    The difference in pressure creates a resultant force upwards (upthrust)
  • Upthrust is why objects appear to weigh less when immersed in a liquid
23
Q

atmospheric pressure

A
  • The atmosphere gets less dense as you go up
  • Air molecules colliding with a surface create atmospheric pressure.
  • atmospheric pressure decreases with an increase in height=less air above surface=less weight
24
Q

what are the typical speeds for walking, running and cycling?

A

walking - 1.5 m/s
running - 3 m/s
cycling - 6 m/s.
car - 10-30 m/s
plane - 200-250 m/s
sound in air - 330 m/s

25
Q

distance equation

A

s=vt

26
Q

why does an object change its velocity when moving in a circle but go at the same speed?

A
  • velocity is speed in a given direction
  • if the direction of an object changes its velocity will change even if it goes at the same speed
27
Q

acceleration equation

A

a=∆ v/t

28
Q

uniform acceleration equation

A

v²-u²=2as

29
Q

what is the acceleration of an object falling near earth’s surface?

A

9.8 m/s2 (falling freely under gravity)

30
Q

what happens to an object falling through a fluid?

A
  • initially accelerates due gravity
  • eventually the resultant force will be zero = object will move at its terminal velocity
31
Q

newton’s 1st law

A
  • if an object is stationary or moving at a constant velocity, the object remains stationary or moving at a constant velocity unless an unbalanced force acts on it
32
Q

what is inertia?

A

The tendency of objects to continue in their state of rest or of uniform motion

33
Q

newton’s 2nd law

A

F=ma

34
Q

newton’s 3rd law

A

for every reaction, there’s an equal and opposite reaction

35
Q

what is stopping distance?

A

thinking distance (distance travelled in driver’s reaction time)+ braking distance (distance travelled until it brakes)

36
Q

what is the average reaction time?

A

0.2-0.9s

37
Q

what affects a driver’s reaction time?

A
  • fatigue
  • drugs
  • alcohol
  • distractions
38
Q

what affects braking distance?

A
  • adverse road+weather conditions eg. wet or icy
  • poor vehicle conditions eg. tyres or brakes
39
Q

what happens when a force is applied to brakes?

A

work done by friction between the brakes and the wheel=reduces Ek of the vehicle+temp of brakes increases

40
Q

what happens to the deceleration of vehicle when it goes at high speed?

A

greater speed=greater braking force=greater deceleration

41
Q

momentum equation

A

p=mv

42
Q

what is the conservation of momentum?

A

In a closed system, the total momentum before an event is equal to the total momentum after the event eg collision or explosion

43
Q

what is the difference between a collision and an explosion?

A

collision=go same direction
explosion=go different directions

44
Q

conservation of momentum equation

A

m1v1+m2v2=mtotalvtotal

45
Q

how does a change in momentum happen?

A

when force acts on an object that’s moving or can move

46
Q

change in momentum equation

A

F =m∆v/t
rate of change in momentum

AQA Physics (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions