Question

A B C D E 10. With the temperature held constant, the pressure of a gas in a cylinder with a movable piston is increased from 30 kPa to 90 kPa.

The initial volume of the gas in the cylinder is 0.6 m^3. What is the

final volume of the gas after the pressure is increased? a) 36 m^3,

b) 0.2 m^3, c) 18 m^3, d) 54 m^3, e) there is no change in volume.

A B C D E 11. A 1.5 kg block of wood is floating in water. What is the magnitude of the buoyant force acting on the block? a) 1.5 N, b) 1500 N,

c) 14.7 N, d) 0.67 N, e) not able to be determined because the amount

of the block under water is not given.

A B C D E 12. A certain boat displaces a volume of 3 m^3 of water. (The density of water is 1000 kg/m^3.) What is the mass of the water displaced by the

boat? a) 29400 N, b) 333 Kg, c) 294 N, d) 3000 kg, e) none of the above.

A B C D E 13. A stream moving with a speed of 0.8 m/s reaches a point where the cross-sectional area of the stream decreases to one-fourth of the original area. What is the water speed in this narrowed portion of the stream? a) 3.2 m/s, b) 0.2 m/s, c) 0.4 m/s, d) 1.6 m/s, e) none of the above.

Answer 1

10]

When the temperature is constant,

Using, PV=nRT

P₁V₁=P₂V₂

V₂= P₁V₁/P₂= 30*0.6/90= 0.2m³

11]

F=Buoyant force acting on the block

P= Density of water

V=Volume of the body inside a water

g=Acceleration due to gravity

F= PVg

In question, the amount of the block underwater is not given so the Buoyant force cannot be determined.

12]

P= Density of water

m= Mass of water

V=Volume of water

P=m/V

m=PV= 1000*3= 3000 kg

13]

Equation of continuity,

A₁v₁=A₂v₂

Given: A₂=1/4(A₁)

v₂= A₁v₁/A₂= 4*v₁=4*0.8= 3.2m/s