Forces and Elasticity

Question 1

Name the three ways in which the shape of an object can be changed

Answer 1

Stretching

Bending

Compressing

Question 2

How can the shape of a stationary object be changed?

Answer 2

When more than one force is acting on the object

Question 3

What force causes a spring to go back to its original shape after being stretched/extended?

Answer 3

Tension

Question 4

Why is it that to change the shape of a stationary object, more than one force has to be applied?

Answer 4

Because if a single force acted on an object, it would simply cause the object to move

Question 5

If an object returns to its original shape when the forces acting on it are removed, has it been deformed elastically or ineslastically?

Answer 5

Elastically

Question 6

If an object does not return to its original shape after the forces acting on it are removed, has it been deformed elastically or inelastically?

Answer 6

Inelastically

Question 7

What is elastic deformation?

Answer 7

When an object returns to its original shape when the forces applied to it are removed

Question 8

What is inelastic deformation?

Answer 8

When an object does note return to its original shape after the forces applied to it have been removed

Question 9

How do you calculate the extension of an object?

Answer 9

Extended length - Original length

Question 10

How do you calculate the compression of an object?

Answer 10

Original length - Compressed length

Question 11

What is the equation of Hooke’s Law?

Answer 11

Force = Spring Constant x Extension (or compression)

Question 12

What is the symbol for spring constant?

Answer 12

K

Question 13

What are the units of the Spring Constant

Answer 13

Newtons per metre

(N/m)

Question 14

What are the units for extension?

Answer 14

Metres

(m)

Question 15

What is the symbol for extension?

Answer 15

e

Question 16

Extenstion is _ _ _ _ _ _ _ _ to the forces applied on an object

fill in the blank

Answer 16

Extenstion is directly proportional to the forces applied on an object

Question 17

Extension is directly proportional to the forces acting on an object, provided that the _ _ _ _ _ _ _ _ _ is not exceeded

fill in the blank

Answer 17

Extension is directly proportional to the forces acting on an object, provided that the limit of proportionality is not exceeded

Question 18

The work done on an object is _ _ _ _ _ to the elastic potential energy

Answer 18

The work done on an object is equal to the elastic potential energy

Question 19

When is the work done on an object not euqal to the elastic potential energy?

Answer 19

When the object is inelastically deformed

Question 20

What is the equation for elastic potential energy?

Answer 20

Ep= 1/2 x K x e^2

Question 21

What is the limit of proprtionality?

Answer 21

The point beyond which the extension of a spring is no longer directly proportional to the force applied to it

Question 22

Beyond the limit of proportionality, the stiffness of a spring decreases making it easier to stretch. Will this make an extension-time graph curve up or down beyond the limit of proportionality?

Answer 22

It will curve up

because as more force is applied, it will be alot more easier to extend so will extend more.

Question 23

Describe the
relationship between the force and the extension when the limit of proportionality has been exceeded

[2 marks]

Answer 23

The relationship is non-linear

as the extension is no longer directly proportional to the force applied