Flashcards in P10- Forces and motion Deck (17):

1

## What is a scalar?

### A scalar is any quantity that has magnitude, but not a direction associated with it. A scalar can be added and subtracted.

2

## What is a vector?

### A vector is any quantity that has both magnitude and direction. It id illustrated by drawing an arrow above the symbol that is used to convey direction and magnitude.

3

## How do you add vector?

### If two similar vectors point in the same direction add them, but if they are going in different directions subtract them.

4

## Examples of scalar

### Density, temperature, frequency, wavelength, pressure, power, potential difference.

5

## Examples of vector

### Magnitude field, velocity, force, momentum, current, acceleration, displacement

6

## Define a force

### A force can change the shape of an object or change its state of rest or its motion.

7

## What do you measure forces in?

### Newtons

8

## When is the resultant force zero

### When all forces are balanced. This means stationary objects remain stationary and moving objects keep on moving at the same speed and in the same direction.

9

## What happens when the resultant force is not zero?

### A stationary object begins to move in the direction of the resultant force and moving objects speed up, slow down or change direction.

10

## How do you calculate a moment?

### Moment= force x distance

11

## A force of 50N is exerted on a claw hammer of length 30cm, calculate the moment

###
M=FxD

M=50x0.3

M=15nm

12

## Moments of the force, can be increased by...

###
Increasing the size of the force.

Using a spanner with a longer handle.

13

## What do gears do?

### They multiply the turning effect of the engine force

14

## What happens when a gear is in low gear?

### The bigger the turning effect is

15

## A gear wheel of radius 20mm is used to turn another gear wheel of radius 10mm with a force of 80N. Work out the moment of a force of a 10mm wheel.

### Moment= force x gear wheel radius = 80N x 0.010m= 0.80Nm

16

## How do you find the centre of mass on a flat object?

### The centre of mass is along the axis of symmetry

17