Solved Examples | Chapter 5 | Pressure & Deformation In Solids | 9th Physics | National Book

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The most elastic material of the following is:
(a) rubber (b) wood (c) glass (d) steel
Hooke’s law hold good up to:
(a) proportional limit (b) yield limit (c) elastic limit (d) plastic limit
A mass of 2kg is hung by spring, which displaces it through 5cm. The spring constant is:
(a) 400N/m (b) 40N/m (c) 4N/m (d) 4000N/m
Materials which does not regain its original shape after removal of t he load producing deformation are termed as:
(a) elastic materials (b) plastic materials (c) rigid materials (d) Hooke’s materials
SI unit of pressure is:
(a) bar (b) newton (c) psi (d) pascal
Which will exert greater pressure?
(a) 3g needle of tip area 1〖mm〗^2 (b) 4000kg elephant of total feet area 0.5m^2
(c) A girl of mass 40kg wearing high heel shoes of cross-sectional area 0.5〖cm〗^2
(d) A loaded ship of mass 2.2×〖10〗^7 kg having area 600m^2
Pressure of 1000 mbars is equivalent to:
(a) 0.1kPa (b) 1kPa (c) 10kPa (d) 100kPa
Pressure of 1mmHg is equal to:
(a) 1.316×〖10〗^(-3) atm (b) 1atm (c) 133.29atm (d) 1.316×〖10〗^5 atm
Atmospheric pressure is commonly measured using a:
(a) hygrometer (b) barometer (c) manometer (d) thermometer
Pressure of liquid in a container increase with:
(a) base (b) volume (c) depth (d) mass
The atmospheric pressure will be smaller at:
(a) Islamabad (b) Peshawar (c) Lahore (d) Murree
A girl of mass 50kg wears heels with an area of 2〖cm〗^2 in contact with the ground. The pressure she exerts on ground is:
(a) 4×〖10〗^(-5) Pa (b) 4×〖10〗^4 Pa (c) 4×〖10〗^(-4) Pa (d) 4×〖10〗^5 Pa
Divers wear special suits in order to protect them from:
(a) low pressure (b) high pressure (c) low temperature (d) high temperature
In a stationary fluid, the local pressure of the fluid vary:
(a) with depth only (b) both with depth and along horizontal direction
(c) horizontally only (d) neither with depth nor along horizontal direction
The pressure exerted by a man on the surface of earth will be smaller then he:
(a) stands on both feet (b) sits on the ground (c) stands on one leg (d) sleeps on the ground

While walking on trampoline. Do you feel more pressure when you stand still or jump up and down? Why does pressure change with movement?
How does the shape of a thumb pin help it penetrate surfaces easily?
If you blow up a balloon and then tie it closed, why does it stay inflated even though you stop blowing? How does pressure play a role here?
Why an airtight layer of a space suit is designed to maintain a constant pressure around the astronaut?
If a liquid has density twice the density of mercury, what will be height of liquid column in barometer?
Why we wouldn’t be able to sip water with a straw on the moon?
How are we able to break a metal wire by bending it repeatedly?
A spring, having spring constant k when loaded with mass ‘m’, is cut into two equal parts. One of the parts is loaded with the same mass m again. What will be its spring constant now?
Why do static fluids always exert a force perpendicular to the surface?
How can a small car lifter lifts load heavier than itself?
Consider a spring with a spring constant of 8000N/m. If a force of 500N is applied to the spring, what will be the displacement of the spring?
In a force multiplier, small piston has diameter of 15cm and large piston has diameter of 30cm. If 250N force is applied on the small piston then how much force will produce on large piston?
A hydraulic car lift lifts a car of mass 1000kg when we apply force of 50N on small piston. Radius of its small piston is 20cm. Find the radius of its large piston.
Water column in a beaker is 70cm. Find the pressure of water in beaker, Take density of water as 1000kg/m^3.
How much force should be applied on an area of 20〖cm〗^2 to get a pressure of 4500Pa?
5.1 Kamil sits on a spring chair as shown in the figure. If Kamil’s weight is 50kg and compresses the spring by about 10cm, when he sits on the chair, find the spring constant of chair’s spring.
5.2 Abdurrahman was standing at the stage of a hall for a speech. What pressure does he apply on the stage if his two feet cover an area of 𝟒𝟎𝟎〖𝒄𝒎〗^𝟐? (b). If for a while he stands on one foot, what will be the pressure under that foot? (Take his mass 50kg)
5.3 A submarine was moving in pacific ocean (largest & deepest ocean) at a depth of 𝟖.𝟓𝒌𝒎. How much pressure is exerted upon the submarine if density of water is 𝟏𝟎𝟎𝟎𝒌𝒈/𝒎^𝟑?
5.4 A hydraulic lift has 𝟎.𝟎𝟎𝟐𝒎^𝟐 narrow cylinder area while 𝟎.𝟗𝒎^𝟐 wider cylinder area. How much force must be applied at the narrow cylinder if a car weighing 𝟏𝟖𝟎𝟎𝒌𝒈 is to be lifted?