"Elasticity" question number distribution across years

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Physics index on skoool nigeria

JAMB questions for "Physics :: Elasticity"

Q1

A string of length 4m is extended by 0.02m, when a load of 0.4kg is suspended at its end. What will be the length of the string when the applied force is 15N?

A

6.08m

B

5.05m

C

4.08m

D

4.05m

E

**Answer:** C

Q2

The diagram above represents the stress-strain graph for a typical metal rod. What does X represent?

A

Yield point

B

Elastic limit

C

Breaking point

D

Proportional limit

E

**Answer:** C

Q3

An elastic material has a length of 36 cm when a load of 40 N is hung on it and a length of 45cm when a load of 60 N is hung on it. The original length of the string is

A

18 cm

B

12 cm

C

20 cm

D

15 cm

E

**Answer:** A

Q4

If the system below is in equilibrium, the tension in the string Q is

A

6N

B

4N

C

11N

D

9N

E

**Answer:** D

Q5

If a force of 50N stretches a wire from 20m to 20.01m, what is the amount of force required to stretch the same material from 20m to 20.05m?

A

250N

B

200N

C

100N

D

50N

E

**Answer:** A

Q6

A piece of stone attached to on end of a string is whirled round in a horizontal circle and the string suddenly cuts. The stone will fly off in a direction

A

tangential to the circular path

B

perpendicular to the circular path

C

towards the centre of the circle

D

parallel to the circular path

E

**Answer:** A

Q7

On top of a spiral spring of force constant 500Nm^{-1} is placed a mass of 5 x 10^{-3}kg . If the spring is compressed downwards by a length of 0.02m and then released, calculate the height to which the mass is projected .

A

2m

B

8m

C

1m

D

4m

E

**Answer:** A

Q8

The diagram below shows the force-extension curve of a piece of wire. The energy stored when the wire is stretched from E to F is

A

1.5 X 10^{-2}J

B

7.5 X 10^{-1}J

C

7.5 X 10^{-3}J

D

2.5 X 10^{-3}J

E

**Answer:** D

Q9

If the tension is maintained on a stretched string of length 0.6m, such that its fundamental frequency of 220 Hz is excited, determine the velocity of the transverse wave in the string

A

66 ms^{-1}

B

132 ms^{-1}

C

264 ms^{-1}

D

528 ms^{-1}

E

**Answer:** C

Q10

A transverse wave is applied to a string whose mass per unit length is 3 X 10^{-2} kgm^{-1}. If the string is under a tension of 12N , the speed of propagation of the wave is

A

40 ms^{-1}

B

30 ms^{-1}

C

20 ms^{-1}

D

5 ms^{-1}

E

**Answer:** C

Q11

If the stress on a wire is 10^{7 }Nm^{-2 }and the wire is strechted from its original length of 10.00cm to streched from its original length of 10.00cm to 10.05cm. The young modulus of the wire is

A

5.0 X 10^{4 }Nm^{-2}

B

5.0 X 10^{5} Nm^{-2}

C

2.0 X 10^{8} Nm^{-2}

D

2.0 X 10^{9} Nm^{-2}

E

**Answer:** D

Q12

The tendon in a man's leg is 0.1m long. If a force of 5 N stretches the tendon by 2.0 x 10^{-5 }, calculate the strain on the muscle

A

5 x 10^{6}

B

5 x 10^{2}

C

2 x 10^{-3}

D

2 x 10^{-7}

E

**Answer:** C

Q13

A load of 20 N on a wire of cross-sectional area 8 x 10^{-7} m^{2} , produces an extension of 10^{-4}m. Calculate Young's modulus for the material of the wire if its length is 3m

A

7.0 x 10^{11} Nm^{-2}

B

7.5 x 10^{11} Nm^{-2}

C

8.5 x 10^{11} Nm^{-2}

D

9.0 x 10^{11} Nm^{-2}

E

**Answer:** B

Q14

A spring of length 25cm is extended to 30 cm by a load of 150 N attached to one of its ends. What is the energy stored in the spring ?

A

3750 J

B

2500 J

C

3.75 J

D

2.50 J

E

**Answer:** C

Q15

A force of 15 N stretches a spring to a total length of 30cm. An additional force of 10 N stretches the spring 5 cm further. Find the natural length of the spring

A

25.0 cm

B

22.5 cm

C

20.0 cm

D

15.0 cm

E

**Answer:** B

Q16

An object of mass 400 g and density 600 kgm^{-3} is suspended with a string so that half of it is immersed in paraffin of density 900 kgm^{-3 }. The tension in the string is

A

1.0 N

B

3.0 N

C

4.0 N

D

5.0 N

E

**Answer:** A

Q17

In an experiment to determine Young's Modulus for a wire, several loads are attached to the wire and the corresponding extensions measured . The tensile stress in each case depends on the

A

load and the extension

B

load and the radius of the wire

C

radius of the wire and the extension

D

extension and the original length of the wire

E

**Answer:** B

Q18

The spiral spring of a spring balance is 25.0cm long when 5N hangs on it and 30.0cm long, when the weight is 10N. What is the length of the spring of the weight is 3N assuming Proke's Law is obeyed?

A

15.0cm

B

17.0cm

C

20.0cm

D

23.0cm

E

**Answer:** D

Q19

In the figure above W1 = 200g and W = 450g. Calculate the extension of the spring per unit load.

A

6.0 x 10^{-5} m N^{-1}

B

2.5 x 10^{-4 }m N^{-1}

C

6.0 x 10^{-3} m N^{-1}

D

2.5 x 10^{-2 }m N^{-1}

E

**Answer:** C

Q20

The figures above show three different ways of hanging heavy picture from a hook. The tension in the string would be

A

greatest in X

B

greatest in Y

C

greatest in Z

D

same in each one

E

**Answer:** A

Q21

An elevator of mass 4800 kg is supported by a cable which can safely withstand a maximum tension of 60 000 N. The maximum upward acceleration the elevator can have is

A

2.5 ms^{-1}

B

5.0 ms^{-1}

C

7.5ms^{-1}

D

10.0ms^{-1}

E

**Answer:** A

Q22

A load of 5 N gives an extension of 0.56cm in a wire which obeys Hooke's law. What is the extension caused by a load of 20N ?

A

1.12 cm

B

2.14cm

C

2.24cm

D

2.52cm

E

**Answer:** C

Q23

Figure 1 below shows two connected bodies of masses m_{1} and m_{2} in equilibrium unit gravity. The tension in the upper string is

A

(m_{1} - m_{2})g

B

m_{1}g

C

m_{2}g

D

(m_{1 }+ m_{1})g

E

**Answer:** D

Q24

A 50.0kg block is dropped on a spring from a point 10m above (Fig. 2). If the force constant of the spring is 4.0 x 10^{4} Nm^{-1}, find the maximum compression of the spring. (take g=10ms^{-2})

A

1.25m

B

0.50m

C

0.25m

D

0.05m

E

**Answer:** B

Q25

A ball attached to one end of a string moves anti-clockwise around a circle whose centre is O. If the string suddenly breaks when the ball is at the point P, along which of the following paths will it move?

A

B

C

D

E

**Answer:** A

Q26

A heavy object is suspended from a string and lowered into water so that it is completely submerged. The object appears higher because

A

the density of water is less than that of the object

B

the pressure is low just below the water surface

C

it experiences an upthrust

D

the tension in the string neutralizes part of the weight

E

**Answer:** C

Q27

A 1000 kg elevator is descending vertically with an acceleration of 1.0 m s^{-2}. If the acceleration due to gravity is 10.0 ms^{-2}, then tension in the suspening cable is

A

1.0 N

B

10.0 N

C

9 000. 0 N

D

11 000.0 N

E

**Answer:** C

Q28

Figure 1 is a graph of force against extension for spiral spring. The force constant of the spring is given by

A

slope of the linear portion of the graph

B

length of the linear portion of the graph

C

area under the linear portion of the graph

D

area under the entire graph

E

**Answer:** A

Q29

Which of the following statements are about the spring balance and the chemical balance?
I. Both are used to measure the mass of an object
II. Either of them may be used to measure the weight of an object
III. The spring balance works on the principle of Hooke's law while the chemical balance works on the principle of moments
IV. A change in gravity changes the readings of a spring balance but not that of a chemical balance

A

I and IV

B

II and III

C

III and IV

D

I, II and III

E

I and III

**Answer:** C

Q30

Which of the following types of motion are oscillatory?
I. A driving board when used by a driver
II. The motion of the balance wheel of a wrist watch
III. The motion of the turn-table of a record player
IV. The motion of the centre of a ten-kobo piece as it rolls own an inclined plane
V. The motion of the needle of a D.C ammeter into which a low A.C current is passed

A

I and II only

B

I, II and III

C

II, III and IV

D

I, II and V

E

III, IV and V

**Answer:** A

Q31

A force of 100 N stretches an elastic string to a total length of 20 cm. If an additional force of 100 N stretches the string 5 cm further, find the natural length of the string

A

15 cm

B

12 cm

C

10 cm

D

8 cm

E

5 cm

**Answer:** A

Q32

In Fig. 2 above, MN is a light uniform metre rule pivoted at O, the 80cm mark. A load of mass 3.0kg is suspended on the rule at L, the 10cm mark. If the rule is kept in equilibrium by a string RP, fixed at P and attached to the rule at R, the 20cm mark, then the tension T in the string is

A

25 N

B

50 N

C

3.5 N

D

6.0 N

E

7.0 N

**Answer:** C

Q33

The total length of a spring when a mass of 20 g is hung from its end is 14cm, while its total length is 16cm when a mass of 30 g is hung from the same end. Calculate the unstreched length of the spring assuming Hooke's law is obeyed.

A

9.33 cm

B

10.00cm

C

10.66cm

D

12.00 cm

E

15.00 cm

**Answer:** B

Q34

The point beyond which a strectched spring does not return to its original length is called the

A

breaking point

B

elastic limit

C

spring constant

D

elasticity point

E

release point

**Answer:** B

Q35

A 10 g mass placed on the pan of a spring balance causes an extension of 5cm . If a 15 g mass is placed on the the pan of the same spring balance the extension is

A

3.3 cm

B

6.5 cm

C

7.5 cm

D

10.8 cm

E

15.0 cm

**Answer:** C

Q36

The extension in a spring when 5 g wt. was hung from it was 0.56 cm. If Hooke's law is obeyed, what is the extension caused by a load of 20g wt?

A

1.12 cm

B

2.14 cm

C

2.52cm

D

2.80 cm

E

2.24 cm

**Answer:** E

Q37

An object of mass m and volume v is totally immersed in a liquid of density p. The tension of a string holding it is

A

mg

B

(m + pv) g

C

(m-pv)g

D

pvg

E

m/m-pv

**Answer:** C

Q38

A piece of rubber 10cm lomg strectches 6 mm when a load of 100 N is hung from it. What is the strain?

A

60

B

6

C

6 x 10-2

D

6 x 10-3

E

0.6

**Answer:** C

Q39

To determine the weight of an object you could

A

use a beam balance

B

use a spring balance

C

find the force necessary to give it a certain acceleration

D

use none of these methods

E

use any of these methods

**Answer:** B

Q40

A solid suspended by a piece of string is completely immersed in water. On attempting to lift the solid out of the water, the string breaks when the solid is partly out of the water . This is because

A

the tension in string decreases as the solid is lifted

B

the mass of the solid has increased

C

the solid apparently weighs less when partially immersed

D

part of the solid still in water is exerting more force on the string

E

the solid is no longer in equilibrum with water

**Answer:** C