P2.3

Question 1

how many forces are needed to stretch, bend or compress an object

Answer 1

2 or more

Question 2

elastic vs plastic deformation

Answer 2

• elastic deformation means the object can return to its original shape after a stretch or squash force has been acted upon it
• Plastic deformation means that the object does not return to its original shape after being squashed or stretched

Question 3

spring constant

Answer 3

F=ke

force = spring constant × extension

spring constant=force/ extension

Question 4

what is the limit of proportionality

Answer 4

• when an object goes past its elastic limit and cant return back to its original form
• meaning it is inelastic and permanently stretched

Question 5

linear vs non- linear

Answer 5

linear :

• obeys hooke’s law
• still elastic,
• hasn’t reached limit of proportionality

non-linear

• disobeys hooks law
• inelastic
• reached the limit of proportionality

Question 6

Recall how to calculate the work done in stretching

Answer 6

elastic potential energy = 0.5 × spring constant(N/m) × (extension m)²

E_e=0.5 x k x e²

Question 7

what happens to gravitational field strength the bigger an object is

Answer 7

it increases and gets stronger

Question 8

define weight and its measurement

Answer 8

• measured in newtons
• weight is a force

Question 9

equation for weight

Answer 9

weight (N)= mass(kg)x gravitational field strength (N/kg)

Question 10

A person has a mass of 60 kg. How much do they weigh on Earth, if the gravitational field strength is 10 N/kg?

Answer 10

• weight = mass × gravitational field strength
• weight = 60 kg × 10 N/kg
• weight = 600 N

Question 11

relationship between the weight of an object and the gravitational field strength

Answer 11

weight of an object and the gravitational field strength are directly proportional