Forces And Elasticity

Question 1

when you apply a force to an object, what might it cause it to do

Answer 1

stretch, compress or bend

Question 2

what requirement needs to be met if you want to bend an object

Answer 2

• more than one force has to be acting on the object

- otherwise the object would simply move in the direction of the applied force instead of changing shape

Question 3

what has happened to an object if it goes back to its original shape and length after the force on it has been removed

Answer 3

it has been elastically distorted

Question 4

what are elastic objects

Answer 4

objects that can be elastically distorted

Question 5

what happens if an object is inelastically distorted

Answer 5

it doesnt turn to its original shape and length after the force on it has been removed

Question 6

what is the elastic limit

Answer 6

• the point where an object stops distorting elastically

- and begins to inelastically distort

Question 7

what is the effect of work being done on an object to stretch or compress it

Answer 7

it causes energy to be transferred to the elastic potential energy stores of the object

Question 8

how much energy is transferred to the elastic potential energy stores of an elastically distorted object when work is done to stretch or compress it

Answer 8

all of it

Question 9

what is the extension of a stretched spring directly proportional to and what is the formula for this

Answer 9

• the load or force applied on it
• so f (is directly proportional to) x
• the load would be when the spring is supported at the top and weights are added to it at its bottom

Question 10

what is the equation for working out the force applied to a spring

Answer 10

• F = k * x

- force = spring constant x extension of the spring

Question 11

what are the units for the force applied on a spring, the spring constant and the extension of the spring

Answer 11

• force applied = N
• spring constant = N/m
• extension of spring = m

Question 12

what does the spring constant depend on

Answer 12

• the material that you are stretching

- a stiffer spring has a greater spring constant

Question 13

what does the equation for the force applied on a spring also work for and how

Answer 13

• it also works for the compression of a spring

- where x is just the difference between the natural and compressed lengths

Question 14

for a linear relationship between force and the extension of the spring, what is the gradient of the objects force-extension graph equal to

Answer 14

its spring constant

Question 15

what is there a limit to regarding the linear relationship between force and extension

Answer 15

theres a limit to the amount of force you can apply to an object for the extension to keep increasing proportionally

Question 16

what is the limit of proportionality

Answer 16

• the point at which the relationship between force and extension are no longer linear (non-linear)
• and the object stretches more for each unit of force

Question 17

how would a force-extension graph look like with the point p representing the limit of proportionality and the point e showing the elsastic limit

Answer 17

• force would be on the y axis and extension would be on the x axis
• the line would start at 0,0 and linearly increase (positive correlation)
• until the line begins to curve downwards
• the point at which the line starts to curve is the limit of porportionality
• as the line continues to curve, the point e would be placed
• this is the point at which the elastically distorted object has been permanently stretched past its elastic limit
• this would usually be placed slightly after the point p