Brainscape's Knowledge GenomeTM

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


See full index

Physics > P10 > Flashcards

P10 Flashcards

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

What is the formula for resultant force?

A

Resultant force(N)= mass(kg) x acceleration(m/s2)

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

Newton’s second law of motion

A

The acceleration of an object is:
Proportional to the resultant force on the object
Inversely proportional to the mass of the object
Resultant force = mass x acceleration

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

Inertia

A

The tendency of an object to stay at rest or continue in uniform motion(constant velocity)

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

What direction is the acceleration in?

A

Acceleration in same direction as velocity
Velocity increases if resultant force is in the same direction as the velocity(positive acceleration)
Velocity decreases if resultant force is in opposite direction to velocity(negative acceleration)

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

How does mass affect acceleration?

A

The greater the mass of an object, the smaller its acceleration for a given force

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

What is weight?

A

The force acting on the object due to gravity - is why an object falls

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

What happens when no forces act on an object?

A

Resultant force is weight - object has constant acceleration of 9.8m/s2, acceleration due to gravity

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

How do mass and weight change?

A

Mass stays the same always, at the equator you weigh less than at the poles since gravity is weaker at the equator

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

Mass

A

Quantity of matter in an object

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

Gravitational field strength

A

Gravitational force on a 1kg object at a place where the object is

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

Earth’s gravitational field strength at the surface

A

9.8N/kg

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

Equation for weight

A

Weight = mass x gravitational field strength(N/kg)

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

Terminal velocity

A

Constant velocity when frictional force on object is equal and opposite to its weight(maximum velocity on an object)

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

Resultant force on object

A

Weight minus frictional force

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

What happens to an object when it falls

A

Acceleration decreases, frictional force increases as it speeds up,resultant force decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How can you ensure an object in the air can reach constant velocity?

A

An object can fall further through the air to reach a constant velocity as the frictional force when an object moves through the air is air resistance

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

When an object falls in the fluid

A

Fluid drags on object due to friction between fluid and surface of moving object, frictional force increases with speed. Object reaches a constant velocity when frictional force is equal and opposite to its weight

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

Object falling in liquid

A

Two forces are drag force and weight

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

Forces on a car

A

For any car travelling at a constant velocity, the resultant force is zero, driving force of engine balanced by resistive forces caused by air resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What affects the braking force

A

Speed of vehicle when brakes are first applied - greater the speed, greater deceleration to stop vehicle in given distance
Mass - greater the mass, greater the braking force for a given deceleration

21
Q

Thinking distance

A

Distance travelled by vehicle in time it takes driver to react, directly proportional to speed, thinking distance = speed x reaction time
To do with the brain:
Level of alertness
Drugs/alcohol
Distractions
Speed of vehicle
Mist and fog don’t affect the thinking distance as they don’t affect the brain.

22
Q

Braking distance

A

Distance travelled by the vehicle during the time the braking force acts
Anything to do with friction between brakes/tyre/road:
Mass of vehicle
Speed of vehicle
State of vehicles’ brakes
Weather
State of the vehicles’ tyres
State of the road(gravel/ice/snow/rain/general condition)
Curve of best fit on graph due to kinetic energy, proportional to v2(speed2)
If you increase the speed, the braking distance increases by speed2:
Doubling the speed quadruples the braking distance
Tripling the speed increases the braking distance by 9 times

23
Q

Stopping distance

A

Thinking distance + braking distance, shortest distance a vehicle can stop in, how far a vehicle will travel between the moment it brakes and the moment it comes to a complete stoo

24
Q

Factors affecting stopping distances

A

Tiredness, alcohol, drugs and mobile phones(distractions) increase reaction time and thinking distance, so increase stopping distance
Thinking distance and braking distance increase with increased speed
In adverse road conditions, drivers brake with less force to avoid skidding, stopping distances greater in poor weather + road conditions
Poorly maintained vehicles with ineffective brakes and tyres take longer to stop

25
Q

Deceleration

A

a = -u2/2s
where u= initial speed
s = distance travelled

26
Q

Deceleration to avoid skidding on a dry flat road

A

No more than 6m/s2

27
Q

Forces needed to accelerate a road vehicle

A

6KN-250KN

28
Q

Momentum

A

Momentum(kg m/s)= mass x velocity, a vector quantity

29
Q

Conservation of momentum

A

In a closed system, momentum same before and after an event as long as there are no external forces

30
Q

Elastic objects

A

If they return to their original shape after the forces deforming it are removed(elastically deformed objects), squash ball, rubber band

31
Q

Extension

A

Length at stage - original length

32
Q

Hooke’s Law

A

The extension of a spring is directly proportional to the force applied as long as the limit of proportionality isn’t exceeded(when spring stretches more than predicred)
Rubber and polythene have a non-linear relationship between their extension and force(low limit of proportionality)
Steel spring has higher limit of priportionality
Force applied = spring constant(N/m) x extension
Applies to a compressed object, change of length is a compression, not an extension

33
Q

Acceleration on moon

A

Lower acceleration due to no air resistance and no atmosphere

34
Q

Being streamlined

A

Streamlined(aerodynamic, smaller surface area), the more streamlined you are, the faster the terminal velocity

35
Q

Parachute

A

1.Hanging from the leg of a helicopter - Weight is equal to tension, no acceleration, balanced forces, terminal velocity
2. Person falling from plane - Weight stays the same, air resistance increases as you fall, big acceleration due to difference between weight + air resistance
3) Air resistance and weight balanced forces, no acceleration
4)Pulling the shoot-
Increasing air resistance due to larger surface area, same weight, unbalanced forces so big deceleration
5)After pulling the shoot - Terminal velocity, air resistance = weight, falling out at a constant speed, balanced forces, slows down so air resistance reduced

36
Q

Is gravity a force?

A

NO!

37
Q

Gravity

A

Acceleration of an object due to the Earth’s mass, the weakest of the fundamental forces

38
Q

What happens to two objects of equal mass

A

They hit the floor at the same time due to equal amounts of graviy acting on them and equal amounts of air resistance acting in them

39
Q

Acceleration in a vacuum

A

In a vacuum, there is no air, so the object continues to accelerate

40
Q

How does gravitational force affect size

A

Planets with a similar gravitational force have a similar size

41
Q

How does mass affect the gravitational force?

A

Objects without mass - no gravitational force
Objects with mass - gravitational force

42
Q

Forces on orbiting objects

A

There are unbalanced forces on orbiting objects, with only the gravitational force acting, since the object accelerates. If you are orbiting, you are weightless as you feel you’re always falling, there is little gravity

43
Q

Forces on unorbiting objects

A

If you’re next to something like the sun without orbiting, you have weight as you’re pulled by the gravitational force of the sun

44
Q

What is an object’s weight in deep space?

A

An object is weightless in deep space, but its mass doesn’t change

45
Q

Does mass affect the acceleration when an object falls?

A

No, because the force could be the weight: acceleration = gravity

46
Q

What affects how far a car goes before it stops

A

Momentum(mass + velocity of a car)
Friction in tyres
Quality of road
Drugs
Tiredness
Brake pads
Type of brakes

47
Q

How does mass affect momentum?

A

The bigger the mass, the more momentum + force needed to stop an object

48
Q

Momentum experiment

A

You could change the height of a slope when trying to test momentum with one block at the end, measure how much block moves.
Measure speed near the end of a ramp.

Physics (2 decks)

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