5. Forces (forces and elasticity and required practical 6 - investigating force and extension on a spring)

Question 1

When a force is applied to an object, what could the object do?

Answer 1

Either bend, stretch or compress

Question 2

What does elastically deformed mean?

Answer 2

When a force is applied then removed, the object will return to its original shape

Question 3

What does inelastically deformed mean?

Answer 3

When a force is applied then removed, the object does not return to its original dimensions

Question 4

What is the equation for force?

Answer 4

F = K (N/m) x e (m)

Question 5

When an object is elastically deformed, where is all the energy transferred to?

Answer 5

The objects elastic potential energy

Question 6

When can the ‘F = ke’ equation be used?

Answer 6

When objects are being stretched or compressed

Question 7

What is the extension at any stage?

Answer 7

length at stage - original length

Question 8

What are force and extension to each other?

Answer 8

directly proportional

Question 9

What is Hooke’s law?

Answer 9

The extension of an elastic object, such as a spring, is directly proportional to the force applied,
provided that the limit of proportionality is not exceeded

Question 10

What is the linear line for a force/extension graph?

Answer 10

• This is elastic region
• It is following Hooke’s Law
• Gradient is k

Question 11

What is the point the graphs stop being linear called?

Answer 11

the limit of proportionality

Question 12

What if there is a non-linear line?

Answer 12

• There is plastic behaviour here
• It is not following Hooke’s Law

Question 13

If the graph for f/e shallow, what does this mean?

Answer 13

• lots of extension for not a lot of force
• easy to stretch

Question 14

What is the limit of proportionality?

Answer 14

The point at which the force and extension of an object are no longer proportional

Question 15

What is required practical 6?

Answer 15

Investigating the relationship between force and extension for a spring

Question 16

What are the steps for the practical?

Answer 16

1. Set up your apparatus
2. Use the same masses and calculate the force using w = mg or measure with a newton metre
3. measure the original length of the spring
4. Add mass, and measure the new length, working out the extension
5. Repeat 6 times
6. Plot the results

Question 17

What is the gradient for an f/e graph?

Answer 17

the spring constant (k)

Question 18

How do you calculate the area under an f/e graph?

Answer 18

elastic potential of a stretched spring
ek = 1/2ke2