p3. forces

Question 1

what are scalar quantities?

Answer 1

only includes magnitude ( size )

Question 2

what are vector quantities?

Answer 2

includes both magnitude and direction

Question 3

how are vector quantities represented?

Answer 3

• vector quantity = arrow
• length or arrow = magnitude
• direction of arrow = direction of vector

Question 4

examples of scalar : vector quantities

Answer 4

• distance : displacement
• speed : velocity
• mass : weight

Question 5

what are contact forces? give examples

Answer 5

objects that are physically touching
- eg. friction,air resistance,tension

Question 6

what are non-contact forces? give examples

Answer 6

objects that are physically separated
- eg. gravitational force,electrostatic force,magnetic force

Question 7

what is work done?

Answer 7

energy transferred ( word done = force x distance )

Question 8

forces involved in stretching

Answer 8

• weight of mass
• reaction of force ( pulling )

Question 9

forces involved in bending

Answer 9

• weight of mass
• reaction of force ( compression )

Question 10

forces involved in compressing

Answer 10

• weight of mass
• reaction of force

Question 11

why is more than one force applied when stretching,bending and compressing an object?

Answer 11

if we only had one force,we would only be moving the elastic object

Question 12

what is elastic deformation?

Answer 12

change of shape due to reaction of applied stress

Question 13

what is inelastic deformation?

Answer 13

material is deformed so much it cannot return to its original shape

Question 14

RP : the relationship between force and extension for a spring

Answer 14

1. secure clamp stand to bench using g-clamp or a large mass
2. use bosses to attach two clamps to clamp stand
3. attach spring to top of the clamp and ruler to bottom of the clamp
4. adjust ruler so it’s vertical, and zero level with the top of the spring
5. measure and record unloaded length of spring
6. hang a 100g mass carrier from spring - measure and record new length of the spring
7. add 100g mass carrier from spring - measure and record new length of the spring
8. repeat steps 1-7 until 1000g