Question 1

An object weighs 10 N on the surface of the Earth. What would be its weight on the surface of the Moon, given that the acceleration due to gravity on the Moon is $$\frac{1}{6}th $$that on Earth?

Accepted Answer

$$1.67\ \mathrm{N}$$

Question 2

Why do camels have broad feet, which help them walk easily on sand?

Accepted Answer

Broad feet increase the area of contact, reducing pressure on the sand.

Question 3

A man is trying to fix a poster to a bulletin board by pressing drawing pins with his thumb. Why is it easier to push the pin into the board with the sharp end rather than the flat end?

Accepted Answer

The sharp end has a smaller area, so the pressure exerted is higher for the same force.

Question 4

If a block is placed on its largest face and then on its smallest face, how does the pressure exerted on the surface change?

Accepted Answer

Pressure increases when placed on the smallest face because area decreases.

Question 5

Which of the following best explains why cutting tools like knives have sharp edges?

Accepted Answer

Sharp edges have a smaller area, increasing pressure for the same applied force.

Question 6

A swimmer feels lighter in water than on land. Which principle explains this phenomenon?

Accepted Answer

Archimedes' Principle

Question 7

According to Archimedes’ Principle, what is the magnitude of the upward buoyant force acting on a body fully immersed in a fluid?

Accepted Answer

It is equal to the weight of the fluid displaced by the body.

Question 8

A block of wood floats on water. What can you say about the weight of the block and the buoyant force acting on it?

Accepted Answer

The weight of the block is equal to the buoyant force.

Question 9

A stone weighs 100 N in air and 80 N when fully immersed in water. What is the buoyant force acting on the stone?

Accepted Answer

$$20\ \mathrm{N}$$

Question 10

Which device is based on Archimedes’ Principle to determine the purity of milk?

Accepted Answer

Lactometer

Question 11

A submarine changes its depth in water by adjusting its density. According to Archimedes’ Principle, what must the submarine do to sink deeper?

Accepted Answer

Increase its density so it becomes greater than the density of water.

Question 12

A 10 kg object is placed on a surface with an area of $$0.5\ \mathrm{m}^2. $$What is the pressure exerted on the surface? (Take $$g = 9.8\ \mathrm{m/s}^2)$$

Accepted Answer

$$196\ \mathrm{N/m}^2$$

Question 13

Which of the following statements about pressure is correct?

Accepted Answer

Pressure is defined as force per unit area: $$P = \frac{F}{A}$$

Question 14

A block of iron and a block of wood have the same volume but different masses. When both are fully immersed in water, which experiences a greater buoyant force?

Accepted Answer

Both experience the same buoyant force because they displace the same volume of water.

Question 15

A person stands on soft sand and sinks more than when standing on hard ground. This is because:

Accepted Answer

The pressure exerted on the sand is higher due to the smaller area of contact.

Question 16

Which of the following best describes the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object; weight is the force with which it is attracted towards the center of the Earth.

Question 17

A hydrometer is used to measure:

Accepted Answer

The density of a liquid

Question 18

If the density of an object is less than the density of the fluid it is placed in, what will happen?

Accepted Answer

The object will float.

Question 19

A 2 kg object is fully immersed in a liquid and experiences a buoyant force of 15 N. If $$g = 10\ \mathrm{m/s}^2$$, what is the apparent weight of the object in the liquid?

Accepted Answer

$$5\ \mathrm{N}$$

Thrust, Pressure, and Weight: Concepts and Applications

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