7/28/2019 38937517-Worksheet-2-12

1/3

Worksheet 2.12 Understanding Elasticity

1. A spring has an original length of 20 cm.

With a load of mass 300 g attached to it, the

length of the spring is extended to 26 cm.

(a) Calculate the spring constant, in N m-1

.

(b) What is the length of the spring when

the load is increased to 500 g ?

Answer : (a) 50 Nm-1 (b) 30 cm

2. Diagram shows the length of a spring before

and after a load of mass 400g is hung on it.

(a) What is the force constant of the spring ?(b) What is the length of the spring with a

load of 500 g ?

(c) What is the load required to extend the

spring to 20 cm ?

Answer : (a) 200 N m-1 (b) 12.5 cm (c) 2 kg

3. A spring has a force constant of 25 N m-1 .

The length of the spring is compressed from

40 cm to 28 cm by a force F.

(a) What is the elastic potential energy

stored in the spring ?

(b) What is the force F required ?

Answer : (a) 0.18 J (b)3 N

4. Figure shows a spring before and after

being compressed by a load.

(a) What is the elastic potential energy

stored in the spring ?

(b) If the spring is released, the load 4 kg

will be thrown upwards. What is the

maximum height reached by the load ?

Answer : (a) 4.8 J (b) 0.12 m

5. Diagram shows 3 spring system. All the

springs used are identical. The original

length of each spring is 12 cm. With a load

of 2 N, the length of each spring becomes

15 cm.

(a) What is the length of x, y and z when a

weight of 8 N is hung on each spring

system ?

(b) Compare the stiffness of the spring

system P and Q.

Answer : (a) x = 48 cm y=18 cm z =42 cm

400 g

4 kg

50 cm26cm

y

z

P Q

7/28/2019 38937517-Worksheet-2-12

2/3

7/28/2019 38937517-Worksheet-2-12

3/3

6. Diagram shows a force- extension graph spring P and spring Q

(a) What physical quantity is represented by

(i) Gradient of the graph

(ii) Area under graph ?

..

(b) State the elastic limit of the spring P.

(c) Which spring is more stiff ? Explain your

answer.

..

..

(c) Calculate the force constant of spring Q in N cm-1

(d) Calculate the elastic potential energy stored in spring Q when the extension is 12 cm.

7. Figure 1 shows the arrangement of apparatus in an experiment to determine the relationship between the

extension e of a spring T with weight W. The relationship of e with W is shown in the graph in Figure 2.

(c) The spring stores energy when it is extended.

(i) Name the form of energy stored in the spring.

..

(ii) Calculate the energy stored in the spring when

it is extend by 4 cm.

F/ N

x/ cm5 10 15

1

2

spring P

spring Q

Slotted

mass

Spring T

W /N

e /cm

1 2 3 4 5 6 7 8

2

4

6

8

10

12

14

16(a) A law states that :

The extension of a spring is directly

proportional to the force applied if the

elastic limit of the spring is not

exceeded.

(i) Name this law.

..

(ii) Mark with a cross (x)

theelastic limit of the spring

on the graph in Figure

Another spring , identical to

spring T , is added to the

arrangement in Figure 1.

This new arrangement is

shown in Figure 3. The

experiment is then repeated.

Sketch the graph of W

against e for this experiment

on the graph in Figure 2.

(d)

Figure 1Figure 2

Figure 3