Flashcards in Unit 2 Section 1 Mechanics Deck (42)

Loading flashcards...

0

## Is force scalar or vector?

### Vector.

1

## What is the difference between a scalar and a vector?

### A vector has magnitude and direction while a scalar only has the former.

2

## What are the 3 rules for bearings?

###
Start from north.

Go clockwise.

Have 3 figures.

3

## What is free fall?

###
The motion of an abject going at an acceleration of g.

The weight is the only force acting on it.

4

## What is a projectile?

### Any object give an initial velocity and then left to move freely under the influence of gravity.

5

## What does a curve on a velocity time graph mean?

### The acceleration is changing.

6

## What is inertia?

### The resistance an object has to a change to its state of motion, including direction and speed.

7

## What affects inertia?

### The larger the mass, the greater the inertia.

8

## What is weight?

### It is the force experienced by a mass due to the gravitational field strength.

9

## What is weight measured in?

### Newtons.

10

## How is weight found?

### Mass X gravitational field strength.

11

## What is the density equation?

### Mass = density X volume.

12

## Define centre of gravity.

### The single point that the whole weight of the object can be considered to act through.

13

## What is the critical angle of an object?

### It is when the centre of mass is on the edge of the base area. The object will be balancing on its edge.

14

## What do free body force diagrams show?

### All the forces the world puts on an object, but not the forces the object puts on the world.

15

## What is resolving a force?

### Splitting up a force into different forces so the calculations are easier to work with.

16

## What is a moment?

### The turning affect of a force.

17

## What is the principle of moments?

### For a body to be in equilibrium, the sum of the clockwise moments about any point equals the sum of the anticlockwise moments about the same point.

18

## What is a couple?

###
A pair of forces of equal size which act parallel to each other but in opposite directions.

They don't produce any resultant linear force but do produce a turning force (or torque)

19

## What is the formula for finding a torque in a couple?

### Torque(Nm) = size of one of the forces(N) X perpendicular distance between the forces (M)

20

## What is Newton's first law?

### The velocity if a object wouldn't change unless a resultant force acts on it.

21

## What is Newton's third law?

###
For every action there is an equal and opposite reaction.

If object A exerts a force on object B, then object B exerts an equal but opposite force on object A.

22

## A book is put on a table. Explain the forces using newton's laws.

###
It is not the third law as gravity pulls down on the books and the table pushes up on the books. These are 2 different sets of forces meaning it isn't an example of the third law.

The forces are equal and opposite meaning nothing moves so it shows the first law.

23

## What are the 2 types of friction?

###
Contact friction. Between solid surfaces.

Fluid friction.(drag or air resistance)

24

## What affects the force of fluid resistance or drag?

###
The viscosity of the fluid.

It increases as speed increases.(normally directly proportional)

The shape of the object. The larger the area, the greater the resistance.

25

## In which direction do frictional forces always act?

###
The opposite direction to the motion of the object.

They never cause things to move on their own.

They convert kinetic energy to heat.

26

## What does terminal velocity look like on an acceleration time graph?

### The acceleration falls to zero.

27

## Define work?

### The amount of energy transferred from one form to another when a force causes a movment.

28

## What is the equation for work?

### Work (J)= force(N)X distance(M)

29