# Practice MCQs For Mass, Weight and Density, Work, Energy and Power

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This quiz contains practice questions for GCE ‘O’ level topics: Mass, Weight and Density, Work, Energy and Power. There are explanations for some of the questions after you submit the quiz. If you could not figure out why a particular option is the answer, feel free to drop a comment below or ask a question in ‘O’ & ‘A’ Level Discussion section of the forum. If you wish to contribute questions to this quiz, please contact us.

The quiz comprises of 10 questions, which are randomly selected from a large pool of questions. After completion, you can refresh the page and try the quiz again for a new set of 10 questions.

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1. When a spring is compressed, what form of energy does it possess?
2. A man weighs 600 N. He runs up stars of total height 4 metres in 3 seconds. How much power is exerted by the man?
3. A rock on the Moon has a mass of 0.5 kg. It is brought to the Earth where the gravitational field is stronger. On the Earth, the rock will have _________ .
4. The mass of a paper-clip is 0.50 g and the density of its material is $8.0 \text{ g cm}^{-3}$. The total volume of a number of paper-clips is $20 \text{ cm}^{3}$.

How many paper-clips are there?
5. The efficiency of an electrical generator is 65%.

What is the useful output that can be expected if the energy input to the generator is 12 kJ?
6. A brick of mass 0.8 kg accidentally dropped from a high scaffolding. It reaches the ground with a kinetic energy of 240 J. How high is the scaffolding? (Take acceleration due to gravity, $g$, to be $10 \text{ ms}^{-2}$.)
7. Which statement is correct about the position of the centre of gravity of a uniform solid?

The centre of gravity of a uniform solid
8. A 2 kg mass is moving at constant speed.

The kinetic energy of the mass is 400 J.

What is the speed of the mass?
9. A boy, who weighs 50 N, runs up a flight of stairs 6.5 m high in 7 seconds.

How much power does he develop?
10. In a laboratory on Earth, experiments show that an object has a mass of 2 kg and a weight of 20 N. The same experiments are then brought to the Moon, where the gravitational field strength is less than on the Earth.

Are the mass and weight of the object the same, or less, than before?

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Back To List of O Level Physics Quiz ### 21 thoughts on “Practice MCQs For Mass, Weight and Density, Work, Energy and Power”

1. This website is very helpful…..Is there chemistry and biology website like this…plz tell me….

2. Consider a stationary box at height x. The block is lifted by a student such that it comes to a rest at higher height y.

Consider the following discussion between two students:

Student 1: I exert an upward force on the box, which moves upward, so I do positive work on the box. The Earth exerts a downward force, so it does negative work on the box. The box begins and ends at rest, so its kinetic energy hasn’t changed. That means that the net work on the box is zero, so the work on the box by my hand and the work on the box by the Earth must have the same absolute value.

Student 2: But the box has moved upward, so its potential energy has increased. That means that the net work on the block must be positive, so the work on the box by your hand must be greater than the work on the box by the Earth.

What can you say about the reasoning given by the two students?
1. They are both incorrect.
2. Student 2 is correct and student 1 is incorrect.
3. They are both correct.
4. Student 1 is correct and student 2 is incorrect.

• student 2 is incorrect as they say that the work done on the box by the hand must be greater than the work done on the box by gravity, which, if it was true, would mean that the box is accelerating. Student 1 however says that the work done on the box must be zero, and have the same value.

idk just guessing

• no

3. volume of ten steel balls =50-20=30
volume of a steel ball=30/10=3 cm^3
mass of a steel ball=27 g
density=mass/volume=27g/3cm^3=9g/cm^3

• Thank you very much
I was also thinking about it when he incorrected it

4. I also have a question.
Which of these have a greater refractive index and why?
A) water
B)ice

1)water, since it has more density
2) ice, since it has more density
3) water, since it has less density
4) ice, since it has less density

• water since it has more density

• so what should i do

5. 1. Ten identical steel balls, each of mass 27 g, are immersed in a measuring cylinder containing 20 cm3cm3 of water.
The reading of the water level rises to 50 cm3 .

What is the density of the steel?

a)8.1 g/cm3
b)13.5 g/cm3
c)9.0 g/cm3[correct]
d)0.90 g/cm3
The volume of the ten steel balls is 50 – 20 = 30 . Density is calculated using Density= mass/volume.

Can someone explain to me why c is correct?
But I think d is correct.

• Each of the steel balls is 27 g.

The total mass will be 27 x 10 = 270 g.

• THNX.: )

• Dont we use 270g for calculating the density

• Coz
Mass of steel ball =27g
Volume of steel ball = 50cm^3- 20cm^3 =30cm^3
Density of steel ball = mass /volume
rho = 27g/30cm^3=0.9gcm^-3.
(By Archimedes’ principle,
volume of body = volume of the liquid displaced by the body.)

• Density=mass/volume
Volume of 10 metal balls =volume of the water that rose
=50-20
=30cm^3
Mass of 10 steel balls=mass of 1 steel ball ×10
=27×10
=270gm
Density=mass/volume
=270/30
=9gm/cm^3

6. good way to test your ability

7. oh wait I get it!! Sorry! 😛 My bad!

8. There is a problem with these tests….. I tick the correct answers but when they show the result, all the answers that I ticked are shown wrong. I mean, they do not check correctly what I ticked. e.g if I ticked the answer c, which is correct, then instead of giving me marks, they think I ticked something else for example d and them tell me the correct answer is c which I eventually did tick.!!!! I AM CONFUSED!

• The answer that you chose is shown in blue, while the correct answer is shown as a tick. If you have chose a wrong answer, it is shown as a cross beside the blue answer.

• • 