Factors Affecting Pressure

Q.

A sharp knife cuts better than a blunt knife. Which of the following options gives the correct reason for this?

1. A sharp knife is costlier than a blunt knife.

2. Sharp knives are usually made of silver which has more strength.

3. A sharp knife has a smaller contact surface area and hence applies more pressure.

4. A sharp knife has larger contact surface area and hence applies more pressure.

Q.

Define pressure.

Q.

It is easier to cut with a sharp knife than with a blunt one. Explain.

Q.

A brick is 32 cm long, 10 cm wide and 10 cm thick. If it weighs 16 Newton and is lying on the ground. Find pressure exerted by brick on the ground.

Q.

Calculate the pressure exerted by a brick which applies a force of 2.5 Newton when it is placed on its widest base (dimensions 25 cm × 10 cm × 5 cm).

Q. Calculate pressure exerted by a cube of side 2 CM having mass 0.5 kg

Q.

Give reason -

The rear wheels of a tractor are broad .

Q.

A sharp knife cuts better than a blunt knife. Which of the following option/options explain this?

1. Blunt knife has a greater surface area in comparison to the sharp knife.

2. Sharp knives are usually made of silver which has more strength.

3. A sharp knife applies more pressure by virtue of its smaller contact surface.

4. A sharp knife has more surface area and hence applies more pressure.

Q. Question 14
A girl stands on a box having 60 cm length, 40 cm breadth and 20 cm width in three ways. In which of the following cases, pressure exerted by the brick will be

(a) maximum when length and breadth form the base
(b) maximum when breadth and width form the base
(c) maximum when width and length form the base
(d) the same in all the above three cases

Q. Explain why the walls of a dam are thicker near the bottom than at the top.

Q.

A block of size 20 m into 10 into 5 M exerts force of 30 Newton calculate the maximum and minimum pressure exerted by block on ground

Q. Why are the rear wheels in a truck more broader as compared to the front wheels

Q. Why Lorries And Trucks Carrying Heavy Loads have 8 tyres instead of Four ??

Q.

A motorcycle weighs 1200 N. If the pressure exerted by one Tyre is 120 Pa, then find the area of tire in contact with the road.

Q.

Calculate the pressure developed by a force of 50N acting on an area of ${10m}^2$.

1. 10 Pa

2. 5 Pa

3. 15 Pa

4. 20 Pa

Q.

A force of 50N is applied normally on a surface of area of $2m^2$. Compute the pressure being applied on the area.

1. 100 Pa

2. 0 Pa

3. 1 Pa

4. 25 Pa

Q.

Is it more comfortable to have thin straps for school bags or broad? Why is that? [2 MARKS]

Q. a box of mass 10 kg has a base area of 1metersquare . find the pressure exerted by it on the ground.(take 1 kgwt = 10 N)

Q.

A girl stands on a box having$60cm$ in length, $40cm$ in breadth, and $20cm$ in height in three ways. In which of the following cases, the pressure exerted by the girl will be

1. Maximum when length and breadth form the base

2. Maximum when breadth and height form the base

3. Maximum when width and length form the base

4. The same in all the above three cases

Q.

A block of mass 2 kg and dimensions 2 cm x 4 cm X 1 cm is kept on a table find the force applied by the block and also find the pressure applied by the surface whose area is 2 cm x 4 cm

Q.

Why do heavy tanks have broad chains called caterpillar tracks

Q. A block weighing 150 g when immersed in water taken in a Eureka can displace 10 mL of water. Find the density of the block.

1. $10g/{\mathrm{cm}}^3$
2. $15g/{\mathrm{cm}}^3$
3. $20g/{\mathrm{cm}}^3$
4. $25g/{\mathrm{cm}}^3$

Q.

A boy exerts a pressure of 48 PA on a box by putting a force of 64N .Calculate the area over which the force is applied .Full explaination

Q.

Name two factors on which the pressure on a surface depends.

Q.

1. A boy weighs 50 N. The area of contact between his two feet is 10 cm². What pressure does he exert on the ground if he stands on one foot?
2. A man weighs 250 N. Suppose he stands on a pointed edge with a base area 5 cm². How much pressure does he exert on the ground?
3. Now compare (a) and (b) to find out the following.

1. Who exerts more force on the ground, the boy in (a) or the man in (b)?
2. Who exerts greater pressure on the ground, the boy or the man?
3. Who is likely to sink into the ground, the man standing on a pointed edge or the boy standing on one foot and why?

Q.

A person applies a force of $36\mathrm{N}$ on an area of $4{\mathrm{m}}^2$. How much pressure is applied?

Q.

How does the broad feet of a camel prevents it from sinking in sand?

Q. How do you increase the pressure by keeping
(a) area unchanged and
(b) force unchanged?

Q.

A man applies a force of 20 N to kill a fly with a flat stick. If the area over which the force is acting is 2 $c{m}^2$, calculate the pressure on that area.

1. Pa

2. Pa

3. Pa

4. Pa

Q. Question 8

A brick is kept in three different ways on a table as shown in Fig. The pressure exerted by the brick on the table will be

(a) maximum in position A
(b) maximum in position B
(c) maximum in position C
(d) equal in all cases