Forces

Question 1

Formula for Weight

Answer 1

Weight = mass x gravitational force

Question 2

Formula for pressure

Answer 2

Force/ Area

Question 3

Formula for density

Answer 3

Mass/ volume

Question 4

Mass

Answer 4

• Measurement of the amount of matter in an object (Kg)
• Mass does not change even when placed at different locations.
• It is NOT a force

Question 5

Weight

Answer 5

• Measurement of the gravitational force acting on an object (N)
• Weight may change with location, depending on the strength of the pull of gravity
• is a force

Question 6

Force

Answer 6

A force is either a push or a pull

Question 7

Contact force

Answer 7

Contact forces are forces that exist between objects that are in contact with each other
E.g. Frictional force, Elastic force

Question 8

Non- contact forces

Answer 8

Non-contact forces are forces that do not require forces to be in contact with each other
E.g. Magnetic force, Gravitational force

Question 9

Gravitational force

Answer 9

The pull exerted by the Earth’s gravity on any object towards the centre of the Earth.

Question 10

elastic force

Answer 10

The force acting on a stretched or compressed object to return it to its original shape.

Question 11

magnetic force

Answer 11

The push or pull exerted between magnets or the pull of magnets on magnetic materials.

Question 12

friction

Answer 12

Friction is a force that opposes motion between surfaces in contact.

Question 13

Pressure

Answer 13

Pressure is the force acting normally per unit area.

Question 14

Resultant force

Answer 14

When a number of forces can effectively be replaced with a single force called the resultant force or net force

Question 15

Positive effects of friction

Answer 15

1. Needed for holding things (prevents slipping)
2. Used in braking pads to slow down cars
3. Provides grip for objects

Question 16

Negative effects of friction

Answer 16

1. Causes heat to be produced (wastage of energy)
2. Causes wear and tear of moving parts in engines, motors and machines

Question 17

Factors affecting friction

Answer 17

1. Type of surface
2. Mass of objects

Question 18

Relationship between the force exerted on an object/ the area on which the force is exerted, and pressure

Answer 18

• For the same area given, the greater the force exerted, the greater the pressure
• For the same force applied, the greater the area in which the force is exerted, the greater the pressure

Question 19

Pressure for liquids

Answer 19

• The deeper the object is, the greater the pressure it experiences due to the liquid
• This is because the deeper an object is, the greater the amount of water presses down on it and hence, there will be more pressure

Question 20

Atmospheric pressure

Answer 20

Atmospheric pressure is the pressure that the air above us exerts one us. It decreases at higher altitudes

Question 21

Density

Answer 21

Density is defined per unit volume

Question 22

Effects of density

Answer 22

• Density of solid is greater than density of liquid= solid sinks
• Density of solid is the same as the density of liquid= solid will be suspended
• density of solid is lower than density of water= solid floats