Flashcards in 3.2 Forces In Action Deck (41)

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1

## Newton's second law.

### F= ma

2

## What are the four fundamental forces of nature?

###
-gravitational force

-electromagnetic force

-weak interaction

-strong interaction

3

##
Which is the weakest of the four fundamental forces?

### Gravitational

4

## What does the electromagnetic force do?

### Holds atoms and molecules together.

5

## How can the electromagnetic force be described?

### The exchange of photons between charged particles of magnetic materials.

6

## What is the weak interaction responsible for?

###
Radioactive decay.

7

## What is the range of the weak interaction?

### 10-18m

8

## What is the strong interaction responsible for?

### Holding subatomic particles together.

9

## What is the strongest fundamental force of nature?

### The strong interaction.

10

## What is the range of the strong interaction?

### 10-15m

11

## What are the five main types of force we need to know about?

### Tension, normal contact force, upthrust, friction and drag.

12

## What is the equation for tension?

### Tension = mass x acceleration.

13

## What is upthrust?

### The upwards force that a liquid or gas exerts on a body floating in it due to the water displaced.

14

## When will an object move at terminal velocity?

### When the magnitude of the body's weight becomes equal to the sum of the drag and the upthrust and the resultant force is 0.

15

## What is a fluid?

### A liquid or a gas.

16

## What is p in the equation for drag?

### The density of the fluid.

17

## What is A in the equation for drag?

### The cross sectional area of the moving object

18

## What is v in the equation for drag?

### Velocity of moving object.

19

## What is equilibrium?

### When all the Coplanar forces are balanced.

20

## How can we work out the resultant of two forces acting on a body?

###
-a scale drawing

-right angled vector triangle.

21

## What does a triangle of forces represent?

###
The direction and magnitude of three coplanar forces that are acting on an object in equilibrium.

22

## Equation for turning moment?

### Magnitude of force (N) x perpendicular distance from a fixed point (m)

23

## Unit of turning moment?

###
N m

24

## Define moment of force or turning moment.

### The product of the and perpendicular distance of its kind of action from the point or axis.

25

## What is the fancy name of the pivot?

### Fulcrum

26

## Define the principle of moments.

### For an object to in rotational equilibrium, the sum of the clockwise moments about a point must be the sum of the anti-clockwise moment about the same point.

27

## What are the two conditions for equilibrium?

###
1) resultant force on the objects must be 0

2) sum of clockwise = sum of anti-clockwise

28

## What is drag?

### Friction force experienced by an object travelling through a fluid.

29

## What is Archimedes principle?

### A law stating that a body totally or partially immersed in a fluid is subject to an upward force equal in magnitude to the weight of fluid it displaces.

30