Write proper word in the blank space.

(a) The SI unit of force is............... (Dyne, Newton, Joule)

(b) The air pressure on our body is equal to........... pressure. (Atmospheric, Sea bottom, Space)

(c) For a given object, the buoyant force in liquids of different.... is................ (the same, density, different, area)

(d) The SI unit of pressure is............... (N/m³,N/m²,kg/m²,Pa/m²)

(a) The SI unit of force is Newton.

Explanation: Newton is the SI (System of International) unit of force. One Newton is equal to 1 kg m/s².Dyne is the CGS unit of force. Joule is the SI unit of work and energy.

(b) The air pressure on our body is equal to atmospheric pressure

Explanation: Different layers of air surrounding the earth constitute the atmosphere. Atmospheric pressure is the force exerted by air on an object per unit area. So the air pressure on our body is the atmospheric pressure itself. Pressure at bottom of sea is equal to the sum of atmospheric pressure and water in sea. Since space has no air molecules, there will be no pressure.

(c) For a given object, the buoyant force in liquids of different density is different.

Explanation: Buoyant force is the force exerted on an object by its surrounding fluid. According to Archimedes principle, force of buoyancy will depends on weight of fluid displaced by the object.

Weight of fluid is the mass of fluid displaced times the acceleration due to gravity. Mass of fluid is the product of density of fluid and displaced volume of fluid. Higher the density of fluid, higher will be the buoyant force.

These relation shows that the force of buoyancy on an object depends on density of surrounding fluid. So, for same object, buoyant force will be different in fluids with different density.

(d) The SI unit of pressure is N/m².

Explanation: Pressure

SI unit of force is N and SI unit of area is m².

So, SI unit of pressure is .