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Pressure in Fluids

Write true or...

Question

Write true or false for each statement :

(a) The S. I. unit of force if kgf.

(b) A force always produces both the linear and turning motions.

(c) Moment of force = force $\times$ perpendicular distance of force from the pivoted point.

(d) Less force is needed when applied at a farther distance from the pivoted point.

(e) For a given thrust, the pressure is more on a surface of a large area.

(g) A man exerts the same pressure on the ground whether he is standing or he is lying.

(h) It is easier to hammer a blunt nail into a piece of wood than a sharply pointed nail.

(i) The S. I . unit of pressure is Pascal.

(j) Water in a lake exerts pressure only at its bottom.

(k) A liquid exerts pressure in all directions.

(l) Gases exert pressure in all directions.

(m) The atmospheric pressure is nearly $10^{5}$ Pa.

(n) Higher we go, greater is the air pressure.

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Solution

(a) The S.I. unit of force is kgf.
Answer. False.
The S.I. unit of force is Newton.

(b) A force always produces both the linear and turning motions.
Answer. False.

(c) Moment of the force = force × perpendicular distance of force – from the pivoted point.
Answer. True.

(d) Less force is needed when applied at a farther distance from the pivoted point.
Answer. True.

(e) For a given thrust, the pressure is more on a surface of large j area.
Answer. False.
For a given thrust, the pressure is less on a surface of a large area.

(f) The pressure on a surface increases with an increase in the thrust on the surface.
Answer. True.

(g) A man exerts the same pressure on the ground whether he is standing or he is lying.
Answer. False.
A man exerts different pressure on the ground whether he is standing or he is lying.

(h) It is easier to hammer a blunt nail into a piece of wood than a sharply pointed nail.
Answer. False.
It is not easier to hammer a blunt nail into a piece of wood than a sharply pointed nail.

(i) The S.I. unit of pressure is Pascal.
Answer. True.

(j) Water in a lake exerts pressure only at its bottom.
Answer. False.

(k) A liquid exerts pressure in all directions.
Answer. True.

(l) Gases exert pressure in all directions.
Answer. True.

(m) The atmospheric pressure is nearly 10⁵ Pa.
Answer. True.

(n) Higher we go, greater is the air pressure.
Answer. False.

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Similar questions

(a) S.I. unit of moment of force is :

(i) N (ii) N cm (iii) kgf m (iv) N m

(b) To obtain a given moment of force for turning a body, the force needed can be decreased by :

(i) applying the force at the pivoted point (ii) applying the force very close to the pivoted point

(iii) applying the force farthest from the pivoted point. (iv) none of the above.

(i) kgf (ii) kg (iii) g (iv) $m s^{- 1}$

(d) The unit of pressure is :

(i) $N \times m$ (ii) kgf (iii) $N m^{- 2}$ (iv) $k g f m^{2}$

(e) Thr pressure and thrust are related as :

(i) Pressure = Thrust (ii) Pressure = Thrust $\times$ Area

(iii) Pressure = Thrust / Area (iv) Pressure = Area / Thrust

(f) A body weighing 5 kgf, placed on a surface of area 0.1 $m^{2}$ , exerts a thrust on the surface equal to :

(g) The feet of lizards act like :

(i) moving pads (ii) drilling pads (iii) suction pads (iv) none of the above

(h) The pressure exerted by a liquid is due to its :

(i) weight (ii) mass (iii) volume (iv) area

(i) The pressure inside a liquid increases with :

(i) increase in depth (ii) decrease in depth (iii) decrease in density (iv) none of the above

(j) The atmospheric pressure at sea level is nearly:

(i) 10 Pa (ii) 100,000 Pa (iii) 100 Pa (iv) 10,000 Pa

(k) Nose bleeding may occur at a high altitude because :

(i) the atmospheric pressure decreases (ii) the oxygen content of the atmosphere decreases

(iii) the atmospheric pressure increases (iv) there are strong air currents at the high altitude

(a) 1 kgf = ______ N (nearly)

(b) Moment of force = ______ $\times$ distance of force from the point of turning

(d) The unit of thrust is ______

(e) Thrust is the ______ force acting on a surface.

(f) Pressure is the thrust acting on a surface of ______ area.

(g) The unit of pressure is ______

(h) Pressure is reduced if ______ increases.

(i) Pressure in a liquid ______ with the depth.

(j) The atmospheric pressure on earth surface is nearly ______

Q. When a force acts on a large area, the pressure it exerts is more.

Q. Indicate whether the following are true or false. Rewrite the false statements correctly.
(a) If we apply the brakes to a moving car, it comes to rest. This shows that force can make a moving object go slower.
(b) When a force of 1 N acts on an area of 1 m² , the pressure exerted is equal to one Pascal.
(c) The foundations of high rise buildings are kept wide so that they exert less pressure on the ground and prevent the building from sinking into the ground.
(d) A boy throws a ball down from the second floor of a building. In this case, gravitational force is acting only on the ball.
(e) Friction helps us to walk more easily on a smooth, highly polished surface.
(f) An old truck tyre will cause more friction with the road than a new tyre.
(g) In the frozen northern regions of Canada, the Eskimos wear large snowshoes as that helps them to walk on freshly fallen snow.
(h) When a force acts on a large area, the pressure it exerts is more.
(i) Gravity and friction are both contact forces.

Q. Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of Earth (or that of another planet). In most circumstances atmospheric pressure is closely approximated by the hydro static pressure caused by the weight of air above the measurement point.Type 1 for true and 0 for false

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