Forces

Question 1

Def non contact force

Answer 1

A force that act through space in fields over a distance

Question 2

Def a lubricant

Answer 2

Is a substance that reduces friction between two moving surfaces

Question 3

Name the effects of a force

Answer 3

Chang position of rest of an object
Change speed or direction of a moving object
Cause rotation
Change in shape

Question 4

State Newtons third law

Answer 4

The mutual similar forces of action and reaction

between 2 bodies

are equal, opposite and collinear

Question 5

State Hooks Law

Answer 5

States that the extension of a spiral spring is directly proportional to the stretching force

provided that the spring is not stretched beyond its elastic limit

Question 6

Give the mathematical expression of Hooks Law

Answer 6

F = ke

Question 7

Def elastic deformation

Answer 7

It is the temporary change in shape of an object which is reversed when the force is removed so that the object returns to its original shape

Question 8

Def limit of proportionality

Answer 8

It is the point beyond which the spring no longer obeys Hooks Law

Question 9

Def strain energy

Answer 9

Is the ability of an object to perform work as a result of a change in shape

Question 10

Def Rotation

Answer 10

Is the effect of a Force

When it is applied to a body

Which is free to move around a point

Question 11

Def fulcrum

Answer 11

The point about which rotation occurs

Question 12

Def a Moment

Answer 12

Product of the force and the perpendicular distance

Of the line of action of the force

From the pivot

Question 13

State the law of Moments

Answer 13

For a lever in equilibrium,

the sum of the clockwise moments

Equals

The sum of the anticlockwise moments

Question 14

Def the centre of gravity.

also centre of Mass

Answer 14

It is the point

At which

The whole weight of the body

Can be considered to act

Question 15

Name 2 ways to increas stability of a body

Answer 15

1) . Lower the centre of mass

2) . Broaden the base of the object

Question 16

Define a lever

Answer 16

It is a device

that can turn about a pivot

Question 17

Name the class of lever utilized in a see saw

Answer 17

1st class

Question 18

Name the class of lever utilized in a nut cracker

Answer 18

2nd Class

Question 19

Name the class of lever utilized in a wheelbarrow

Answer 19

2nd Class Lever

Question 20

Name the class of lever utilized in braaivleis tongs

Answer 20

3rd Class Lever

Question 21

State the Triangle Law

Answer 21

When 3 forces are in equilibrium

they can be represented in both magnitude and direction

by the 3 sides of a triangle

Taken in order

Question 22

Define a Newton

Answer 22

It is the force which gives a mass of 1kg an acceleration of 1m/s

Question 23

State Newtons 2nd law

Answer 23

When a resultant force is applied to a body

it produces an accelerationin the direction of the force

That is directly proportional to the force

and inversely proportional to the mass of the object

Question 24

Define a contact force

Answer 24

Is a force that is extended directly on an object