Force Moments Work And Power

Question 1

Forces

Answer 1

A force is anything which causes an object to change its velocity
Force is measured in Newton’s

Question 2

Friction

Answer 2

Friction is the force that prevents easy movement between two objects in contact
• High friction : Sand paper, Car Tyres and rough soled shoes
• Low Friction: wet soap, ice and glass

Question 3

Weight

Answer 3

• Weight = mass x gravity
• What is the weight of an object of mass 6.5 kg?
• Calculate the weight of an object of mass 200g.
• What is the mass of a person whose weight is 620 N?

Question 4

Hooke’s Laws

Answer 4

Hooke’s Law states that the extension of an elastic body (a spring) is directly proportional to the force applied to it

Question 5

Forces always occur in pairs

Answer 5

• For every force there is an equal opposit force

Question 6

Measuring Forces

Answer 6

To measure force we use a newton meter also called a spring balance
• Can you find the force of your pencil case?
• 1kg has a force of 10N

Question 7

Force Quantities in every day life

Answer 7

A
•a.
•b. •c. •d. •e.
•f.
Newton is a very small unit
1N to lift an Apple
12N to lift your textbook
20N to open a can of Coke 50N to squash an egg
100N or more to push a supermarket trolley
Car brakes can exert a force of about 5000N on wheels to stop the
car.
Force Quantities in every day life

Question 8

Friction

Answer 8

Friction is the force that prevents easy movement between two objects in contact
• High friction : Sand paper, Car Tyres and rough soled shoes
• Low Friction: wet soap, ice and glass

What woul

Question 9

LUBRICANT

Answer 9

• A LUBRICANT is anything that reduces friction

Question 10

Work

Answer 10

• Work is done when a force moves an object
• We can find the amount of work done by multiplying the force used by the distance moved
Work (j) = Force (N) x Distance (m)
Work and energy are measured in joules

Question 11

Power

Answer 11

Is the rate at which work is done

Power is measured in Watts where 1 watt =1j/s

Power (w) = Work done (j) Time (s)

Question 12

4 advantages of friction

Disadvantage

Answer 12

Driving,walking,nailys,sports playable

Break cars,foret fires,bones artistries