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Flashcards in Physics IGCSE Deck (133)
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1

What are the units of gravitational field strength?

N/kg or m/s^2

2

average speed =

speed = distance/time

3

How do you determine the displacement from a velocity-time graph?

Area under the curve

4

What are the effects of a force?

change in velocity over time (acceleration); change in shape

5

What is friction?

A force which opposes motion

6

Describe the forces acting on falling objects and describe how they reach terminal velocity

The object initially accelerates toward the Earth due to the gravitational force. As the object's velocity increases, so too does its air resistance. Eventually, the force of air resistance = gravitational force, so the forces will be balanced. According to Newton's 1st Law, unless acted on by a force, an object will travel at constant velocity

7

Stopping distance =

s.d. = thinking distance + braking distance

8

What factors affect thinking distance?

Metal condition of driver; tiredness; influence of drugs; alcohol; medication; level of concentration

9

What factors affect braking distance?

speed; road conditions; tyre conditions; car mass; brake conditions

10

What is the centre of gravity?

the point within something at which gravity can be considered to act

11

Moment =

Moment = Force x Perpendicular distance

12

What is Hooke's Law?

The extension of an elastic material is proportional to the force applied until the material reaches its elastic limit

13

What is an elastic material?

A material which will retain its original shape after a force which has been deforming it has been removed

14

What celestial body do comets orbit?

The Sun

15

How do planets orbit the Sun?

In nearly circular orbits

16

Describe the orbit of a comet

Comets have very elliptical, elongated orbits. They travel much faster when moving near to the Sun, because the gravitational force is much stronger (the force is inversely proportional to the square of the distance from the centre of gravity)

17

orbital speed =

o.s. = 2πr/T

18

What is the universe?

Collection of billions of galaxies

19

What is the Milky Way galaxy?

Our galaxy; a collection of billions of stars

20

What is the solar system?

Collection of all the celestial bodies (planets, natural satellites, comets, asteroids etc.) which orbit the Sun

21

What is current measured in?

Amperes (Amps)

22

What is charge measured in?

Coulombs

23

What is energy measured in?

Joules

24

What is resistance measured in?

Ohms

25

What is potential difference measured in?

Volts

26

What is power measured in?

Watts

27

What does current in a resistor cause?

Transfer of electrical energy to heat energy and an increase in temperature (e.g. in a kettle's element)

28

Power =

P=IV

29

Energy =

E=IVt

30

Is mains electricity AC or DC?

Alternating Current