Forces Flashcards Preview

AQA GCSE Physics > Forces > Flashcards

Flashcards in Forces Deck (99)
Loading flashcards...
1

What do scalar quantities have?

Magnitude

2

What do vector quantities have?

Magnitude and direction

3

How are vectors represented?

To scale with an arrow:
-specific length representing magnitude
-head representing the direction

4

Give examples of scalar quantities:

distance, speed, mass, time, temperature, energy

5

Give examples of vector quantities:

displacement, velocity, acceleration, weight, momentum

6

What do combined vectors give?

A single resultant

7

What are the steps to find the resultant vector of two vectors at right angles?

1) choose scale for drawing
2) draw the two given vectors carefully, measuring the angle between them
3)complete the rectangle/parallelogram
4) draw the diagonal
5) measure the length and angle of the diagonal

8

What can a resultant vector be turned into?

Its vertical and horizontal components

9

How do planes keep on their desired course despite the wind?

The pilot has to adjust the velocity vector of the plane to compensate -they would have to determine a velocity relative to the wind speed and direction to ensure travel on the desired course

10

What is a contact force?

A force which requires physical contact for interaction (ie. to do work)

11

What is a non-contact force?

A force which requires no physical contact for interaction/ to do work

12

What are examples of contact forces?

friction, tension, air resistance, normal contact force

13

What are examples of non-contact forces?

-gravitational attraction or weight
-magnetism
-electrostatic force

14

What is the principle of a gravitational force?

A massive body will cause another massive body to accelerate ie. a body's speed and/or direction will change when the body is in a gravitational field

15

What is weight?

The result of the acceleration due to gravity

16

How do we calculate weight?

weight = mass x acceleration due to gravity
W = mg

17

What is the unit for weight?

Newtons

18

What value has the units N/Kg?

Gravitational field strength

19

What value has m/s^2?

Acceleration due to gravity

20

What is the relationship between weight and mass?

they are directly proportional

21

What type of quantity is mass? what does this mean?

- an invariant quantity which means it is not dependent on the location of the body

22

What type of quantity is weight? what does this mean?

- a variable quantity which means it is dependent on the acceleration due to gravity at the location of the body

23

What do we use to measure weight?

a calibrated spring balance (Newtonmeter)

24

What is the centre of mass/gravity?

the point associated with a body through which its weight appears to act

25

Where is the centre of mass for a regular lamina?

At the geometric centre of it

26

How would you find the centre of mass for an irregular lamina?

- freely suspend the lamina and a plumb line from three different points on the lamina
- the plumb line will hang along a vertical line that contains the lamina's centre of mass
- where the three lines cross, is the location of the lamin'a centre of mass

27

What is work done?

the energy transferred by a force changing the displacement of a body

28

What is the equation for work?

W = Fs

29

What is the equivalent of 1J of work?

1 Nm

30

What is the work-energy theorem?

When work is done that causes a change in a body's velocirt, there is a corresponding change in the body's kinetic energy