Pressure

Q.

$3$ applications of pressure for class $8$.

Q. When we drink a soft drink with the help of a straw, what forces the liquid up the straw?

Q. What are the characteristics of liquid pressure?

Q.

Football shoes have studs under them. What could be the reason for this?

1. The smaller area of the studs creates smaller pressure and thus the shoes sink into the ground.

2. It helps to run faster without slipping off the ground.

3. Studs help to make higher jumps.

4. The smaller area of the studs creates larger pressure and thus the shoes sink into the ground, providing a better grip.

Q.

What is liquid pressure? Mention the properties of pressure exerted by liquids.

Q. The force acting perpendicular to the surface is called and the thrust acting per unit area is called .

1. pressure
2. thrust
3. force
4. volume

Q.

What happens to the shape of a hot tin can when cold water is poured in it?

1. The pressure inside the tin is more than that outside, so it shrinks.

2. The pressure inside the tin is less than that outside, so it shrinks.

3. The pressure outside the tin is same as that inside, so the shape remains the same.

4. The pressure inside the can is equal to the atmospheric pressure - final shape depends on the atmospheric pressure.

Q.

A siphon in use is demonstrated in the following figure. The density of the liquid flowing in siphon is 1.5 gm/cc. The pressure difference between the point P and S will be

1. 10⁵ N/m

2. 2 × 10⁵ N/m

3. Zero

4. Infinity

Q.

The pressure in a fluid at rest is the same at all points if they are at the same height this law is called_________________.

Q.

Why do skis not sink into snow too far ?

1. Skis have a large area to reduce the force on the snow.

2. Skis have a large area to reduce the pressure on the snow.

3. Skis have a small area to reduce the pressure on the snow.

4. Skis have a large area to increase the pressure on the snow.

Q.

Explain the following:

A. Why do mountain climbers need oxygen tanks while going on high altitude?
B. If you climb a mountain without any equipment, your nose will start to bleed. Why? [5 MARKS]

Q. The pressure exerted by the brick on the table will be maximum in the position

1. A
2. B
3. C
4. Same for all

Q. A force of $15N$ is applied on a body over a surface area of 25 $m^2$. Calculate the pressure applied on the surface.

1. 0.6

Q.

Two vessels with equal base and unequal height have water filled to same height. The force at the base of the vessels is

Q.

A $50N$ force is applied on an area of $2m^2$. Compute the pressure.

1. $100Pa$

2. $0Pa$

3. $1Pa$

4. $25Pa$

Q.

A bottle kept on a table started leaking at equal rates when two holes were made at the same level. This is because_______.

1. the liquid exerts equal pressure in all directions at the same level

2. the liquid does not exert any pressure

3. the liquid exerts unequal pressures in different directions at the same level

4. the liquid exerts pressure only at one hole and not at the other hole

Q. The A, B, and C vessels are filled with the liquid of the same height. The bottom area of A is equal to the bottom area of B and is less than the bottom area of C.
Which of the following relation is correct for the value of the force at the bottom?
($F_A,F_B\text{and}{F}_C$ are the force values at the bottom for A, B and C respectively.)

1. $F_A=F_B=F_C$
2. $F_A>F_B>F_C$
3. $F_A<F_B<F_C$
4. $F_A=F_B<F_C$

Q.

A force applied on an area of 0.5 $m^2$ causes a pressure of 250 Pa. What was the force applied?

1. 1 Pa

2. 0 Pa

3. 25 Pa

4. 100 Pa

Q. Why are dams made thicker at the bottom?

1. To generate more electricity
2. To store more water
3. To withstand the high pressure at the liquid at the bottom
4. To withstand atmospheric pressure

Q.

Thrust is a ____ quantity.

Q. Why does air come out of a tyre when it is punctured?​

Statement 1: Air pressure inside the tyre increases after being punctured.​

Statement 2: The air outside the tyre is at a higher pressure than the air inside the tyre. ​

1. Both the statements are incorrect.​
2. Statement 2 is correct but statement 1 is incorrect.​
3. Both the statements are correct.​
4. Statement 1 is correct but statement 2 is incorrect.​

Q. The pressure inside a liquid increases as the depth decreases.

1. True
2. False

Q. Which among these is a wrong statement?

1. Long flat skies exert less pressure on snow.
2. Broader feet exert less pressure.
3. Sharp knife edge exerts less pressure.
4. Sharp knife edge exerts more pressure.

Q.

The atmospheric pressure at the surface of the earth is ${10}^{5}N{m}^{-2}$. How much thrust acts on a man whose average surface area is $3m^2$ ?

Q. A $10N$ force is applied on a cube of side $2m$. Calculate the thrust $\left(T\right)$ and pressure $\left(P\right)$ acting on the cube .

1. $T=5N$
   $P=10N$
2. $T=5N$
   $P=5N$
3. $T=10N$
   $P=2.5N$
4. $T=2.5N$
   $P=10N$

Q.

Which of the following object exerts more pressure on the floor? (All object have the same mass).

1. 

2. 

3. 

4. 

Q. In which direction does air exerts pressure?

1. In all directions
2. Upward direction only
3. Downward direction only
4. Sideways only

Q. Statement 1: If same force acts on two surfaces, more pressure is applied on the surface with the smaller area.
Statement 2: Pressure is defined as thrust per unit area.

1. Both statements are true and Statement 2 is not the correct explanation of Statement 1.
2. Both statements are true and statement 2 is the correct explanation of statement 1.
3. Statement 1 is false and Statement 2 is true.
4. Statement 1 is true and Statement 2 is false.

Q.

Pressure can be measured in terms of

1. True

2. False

3. Pa

4. Newton

Q. Usually the atmospheric pressure is equal to ___________.

1. $1.013\times {10}^5$ Pascal
2. $101.3kPa$
3. $1.013\times {10}^{5}N/m^2$
4. all of the above