Forces can be of two types:
(i) Contact forces.
(ii) Non-contact forces.
(i) Contact forces : The forces that come into play when two objects come in contact with each other.
(a) Muscular force: The force which is exerted due to action of muscles is known as the muscular force. e.g., running, bending, walking etc.
(b) Frictional Force: The force responsible for changing the state of motion of an object. Equal and opposite forces are being exerted on an object when its surface comes in contact with other surface. e.g., a car or scooter comes to rest.
(ii) Non-contact forces: The forces that can be exerted from a distance without establishing a contact are called the non-contact forces.
(a) Magnetic forces : Force exerted by a magnet on another magnet or magnetic substances like iron is called magnetic force. e.g., Car sticking to an electromagnet.
(b) Electrostatic force : Force exerted by a charged body on another charged body or uncharged body is called electrostatic force. e.g., If we rub a comb with hair and bring it near some small bits of paper it attracts the bits of paper towards itself. This is electrostatic force.
(c) Force of gravity : The earth pulls every object towards its centre. The force exerted by the earth is called the force of gravity.

Pressure exerted by liquids and gases on the wall of container can be explained by the following experiments. Take a plastic bottle. Fix a cylindrical glass tube (a few ems long) near its bottom. Make sure that the water does not leak from the joint. Cover the mouth of glass tube with a thin rubber sheet. Fill the bottle up to half with water. The bulging of the rubber sheet in this case indicates that water exerts pressure on the sides of container or we can say that liquid exerts pressure on the walls of container. In the case of gas, when we inflate a balloon the balloon will be filled with air and air exerts pressure and its shape has changed. So we find that gases, too, exert pressure on the walls of their container.

Across:
(1) Friction,
(2) Gravity,
(3) Muscular,
(4) Magnitude
Down:
(5) Force
(6) Non-contact
(7) Motion
(8) Force.

(a) Sumit applied more pressure on his palm by baring the maximum load of his body on small  area of palm while Amit applied less pressure on his palm by baring the same load on larger area of palm.
(b) Amit have the presence of mind and he thought of an excellent idea about pressure on the body part.

(a) In horse pulling a cart situation muscular force is involved.
(b) Due to magnetic force, a sticker attached to steel almirah without the glue.
(c) Due to gravitational force, a coin gets fall down on the ground on slipping from the hand.
(d) Due to electrostatic force, a plastic comb rubbed in dry hair picked up tiny particles of hair.
(e) Due to frictional force, a moving boat coming to rest when rowing is stopped.

(a) Here, F = 50N, A = 5 cm² = 5 x10^-4 m²
\(\therefore p=\frac{F}{A}=\frac{50}{5\times10^{-4}}=10^{5}\) Pa
(b) Here, area changes to 50 cm²= 50 x 10^-4 m²
\(\therefore p=\frac{F}{A}=\frac{50}{5\times10^{-4}}=10^{4}\)Pa
(c) Here the values displayed by the teacher is the experience and his ideality.

It is difficult to cut cloth using a pair of scissors with blunt blades because blunt blades have more area and due to which applied force produces very less pressure.
As we know that pressure is inversely proportional to area of cross-section, so it is difficult to cut cloth from blunt blades. \((\therefore \rho=\frac{F}{A})\).

Pressure at depth due to liquid column depends upon
(i) gravitational acceleration (g)
(ii) density of liquid
(iii) height of liquid.
And in this case, g and density are same, so only thing that can change pressure is height. So, the order of pressure exerted by the fluid A, B,C and D at the base is given by P_o > P_a > P_A > P_C

While walking on a sandy surface, one needs the footwears of larger area so that the pressure exerted on the ground is minimum. So, in this case, the woman having the sandals with pointed heels will be less comfortable in walking while the other woman wears sandals with flat sales feels more comfortable while walking on sandy beach.

Since, if a person is walking on the ground, then at one time his one foot is only on the ground. Therefore, the force of entire weight of man falls on smaller area of the ground which results into large pressure on the ground. While in another case, if the man is standing on the ground, then both his feet are on the ground. It causes the force of weight of man, falls on larger area of ground and results in less pressure on the ground.