Forces

Question 1

What are the 3 contact forces?

Answer 1

• Friction
• Air resistance
• Tension

Question 2

What are the 3 non-contact forces?

Answer 2

• Weight
• Magnetic force
• Electrostatic force

Question 3

State 2 ways friction is useful in daily lives.

Answer 3

Walking, writing on paper, lighting a fire, parachuting.

Question 4

State 2 ways friction is a nuisance in daily lives.

Answer 4

Wear and tear of moving parts, reduces efficiency in machines, reduces speed.

Question 5

What are 2 ways to reduce friction?

Answer 5

Attach wheels to the bottom of an object, use lubricant or polishing the surfaces.

Question 6

What is the definition of non-contact force

Answer 6

A force that acts on an object without touching it.

Question 7

What is the definition of mass?

Answer 7

Amount of matter in a body.

Question 8

What is the definition of weight?

Answer 8

Force of gravity acting on a body.

Question 9

What is the SI unit of mass and weight?

Answer 9

Mass: Kilogram
Weight: Newton

Question 10

What is used to measure mass?

Answer 10

Beam/electronic balance

Question 11

What is used to measure weight?

Answer 11

Spring balance

Question 12

Which, mass or weight, is dependant on location (gravitational field strength)?

Answer 12

Weight.

Question 13

What is the formula for weight?

Answer 13

Weight = Mass × gravitational field strength

Question 14

State two uses of forces in daily lives.

Answer 14

Opening a door, pressing a button in a lift, squeezing a tube of toothpaste, turning on a tap.

Question 15

What are the effects of forces on the shape of an object?

Answer 15

Change in shape and size of an object.

Question 16

What are 2 effects of forces on the motion of an object?

Answer 16

• Move a stationary object.
• Change direction in which an object is moving.
• Change speed of the moving object.
• Stop a moving object.

Question 17

What is pressure?

Answer 17

The amount of force exerted per unit area.

Question 18

What is the formula for pressure?

Answer 18

Pressure = Force ÷ Area

Question 19

What is the symbol, SI unit and SI unit symbol for pressure?

Answer 19

P, pascal, Pa

Question 20

State how pressure is used in everyday life.

Answer 20

Using fingers to apply force on the head of a thumbtack to allow the pin to pierce paper and wooden boards.

Question 21

How do straws work?

Answer 21

By sucking through the straw, we lower the air pressure in the straw. The higher atmospheric pressure outside the straw pushes the liquid up the straw.