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

Show/Hide Sub-topics (Mass, Weight and Density | O Level)

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.

Back To O Level Physics

Back To List of O Level Physics Quiz

1. Inertia is the resistance of a object to any change in its state of motion, including a change in direction. Which property is a measure of the body's inertia?
2. When a spring is compressed, what form of energy does it possess?
3. When a nucleus of Uranium-235 absorbs a neutron, nuclear fission occurs. In a typical reaction, the total mass decreases by $3 \times 10^{-28}$ kg.

Given that the speed of light c is $3 \times 10^{8}$ m/s, approximately how much energy is released?

Hint: (Use Einstein's mass equivalence equation: $E = mc^{2}$)
4. 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?
5. A machine is able to lift 200 kg of bricks vertically up to a height of 30 m above the ground in 50 s. What is the power of the machine? (Take the acceleration due to gravity, $g$, to be $10 \text{ ms}^{-2}$.)
6. A crane lifts a load of 6000 N through a vertical distance of 15 m in 30 s.

What is the average useful power during this operation?
7. Which of the following about energy is false?
8. An object is lifted at constant speed through a distance h metres above the ground in t seconds. The potential energy gained by the object is equal to
9. A car is driven along a level road. The total energy input from the petrol is 60 kJ, and the car wastes 45 kJ of energy.

What is the efficiency of the car?
10. 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?

Back To O Level Physics

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.

• • 