4.5.1 Forces And Their Interactions

Question 1

What do scalar quantities have ?

Answer 1

Magnitude only

Question 2

What do vector quantities have ?

Answer 2

Magnitude and an associated direction

Question 3

How is a vector quantity represented?

Answer 3

By an arrow

• the length represents the magnitude
• the direction represents the direction of the vector quantity

Question 4

What is a force?

Answer 4

A push or pull that acts on an object due to the interaction with another object

Question 5

What are contact forces?

Answer 5

The objects are physically touching

Question 6

What are non- contact forces ?

Answer 6

The objects are physically separated

Question 7

Examples of contact forces

Answer 7

• friction
• air resistance
• tension
  And normal contact force

Question 8

Examples of non- contact forces

Answer 8

• gravitational force, electrostatic force and magnetic force

Question 9

Force is a ________ quantity

Answer 9

Force is a vector quantity

Question 10

What is weight ?

Answer 10

The force acting on an object due to gravity

Question 11

Why is the force of gravity close to the Earth?

Answer 11

Due to the gravitational field around the Earth.

Question 12

The weight on an object depends on what?

Answer 12

The gravitational field strength at the point where the object is

Question 13

Weight equation y

Answer 13

Weight =mass x gravitational field strength
[W = m g ]
weight, W, in newtons, N
mass, M, in kilograms, Kg

Question 14

What is the “centre of mass”?

Answer 14

Where the weight of an object may be considered to act at a single point referred to as the object’s “centre of mass”.

Question 15

What are directly proportional?

Answer 15

The weight of an object and the mass of an object

Question 16

How is weight measured?

Answer 16

Using a calibrated spring- balance (a newton meter)

Question 17

What is the Resultant force?

Answer 17

When a number of forces acting on an object may be replaced by a single force that has the same effect as all the original forces acting together, the single force being the resultant force

Question 18

A single force can be resolved into __ components acting at _ to each other. The - component forces together have the same effect as the single force

Answer 18

A single force can be resolved into two components acting at right angles to each other. The two component forces together have the same effect as the single force