Question: A ping-pong ball has an average density of 0.0840 g/cm³ and a diameter of 3.80 cm. What force would be required to keep the ball completely submerged under water? (0.258 N)
Answer Options:
0.100 N
0.200 N
0.258 N
0.300 N
Answer: 0.258 N
Question: A cube of wood of density 0.78 g/cm³ is 10 cm on a side. When placed in water, what height of the block will float above the surface? (2.2 cm)
Answer Options:
1.0 cm
2.2 cm
3.5 cm
5.0 cm
Answer: 2.2 cm
Question: What is the total mass of the Earth’s atmosphere? (The radius of the Earth is 6.4 x 10⁶ m, and atmospheric pressure at the surface is 10⁵ N/m².) (5 x 10¹⁸ kg)
Answer Options:
2 x 10¹⁸ kg
3 x 10¹⁸ kg
5 x 10¹⁸ kg
7 x 10¹⁸ kg
Answer: 5 x 10¹⁸ kg
Question: The water behind Grand Coulee Dam is 1 200 m wide and 150 m deep. Find the hydrostatic force on the back of the dam. (13.2 x 10¹⁰ N)
Answer Options:
10.0 x 10¹⁰ N
13.2 x 10¹⁰ N
15.0 x 10¹⁰ N
20.0 x 10¹⁰ N
Answer: 13.2 x 10¹⁰ N
Question: The bottom of a flat-bottomed aluminum boat has an area of 4.0 m² and the boat’s mass is 60 kg. When set afloat in water, how far below the water surface is the boat bottom? (0.015 m)
Answer Options:
0.010 m
0.015 m
0.020 m
0.025 m
Answer: 0.015 m
Question: A blimp is filled with 400 m³ of helium. How big a payload can the balloon lift? (The density of air is 1.29 kg/m³; the density of helium is 0.18 kg/m³.) (444 kg)
Answer Options:
300 kg
400 kg
444 kg
500 kg
Answer: 444 kg
Question: An ideal fluid flows through a pipe made of two sections with diameters of 1.0 and 3.0 inches, respectively. The speed of the fluid flow through the 3.0-inch section will be what factor times that through the 1.0-inch section? (1/9)
Answer Options:
1/9
1/3
3
9
Answer: 1/9
Question: The flow rate of a liquid through a 2.0-cm-radius pipe is 0.008 0 m³/s. What is the average fluid speed in the pipe? (6.4 m/s)
Answer Options:
3.2 m/s
6.4 m/s
9.6 m/s
12.8 m/s
Answer: 6.4 m/s
Question: An ideal fluid, of density 0.90 x 10³ kg/m³, flows at 6.0 m/s through a level pipe with radius of 0.50 cm. The pressure in the fluid is 1.3 x 10⁵ N/m². This pipe connects to a second level pipe, with radius of 1.5 cm. Find the speed of flow in the second pipe. (0.67 m/s)
Answer Options:
0.33 m/s
0.67 m/s
1.0 m/s
1.5 m/s
Answer: 0.67 m/s
Question: Water flows at 15 m/s through a pipe with radius 0.040 m. The pipe goes up to the second floor of the building, 3.0 m higher, and the pressure remains unchanged. What is the speed of the water flow in the pipe on the second floor? (13 m/s)
Answer Options:
10 m/s
13 m/s
15 m/s
18 m/s
Answer: 13 m/s
Question: A solid object is made of two materials, one material having density of 2 000 kg/m³ and the other having density of 6 000 kg/m³. If the object contains equal volumes of the materials, what is its average density? (4 000 kg/m³)
Answer Options:
2 000 kg/m³
3 000 kg/m³
4 000 kg/m³
5 000 kg/m³
Answer: 4 000 kg/m³
Question: A 15 000-N car on a hydraulic lift rests on a cylinder with a piston of radius 0.20 m. If a connecting cylinder with a piston of 0.040-m radius is driven by compressed air, what force must be applied to this smaller piston in order to lift the car? (600 N)
Answer Options:
400 N
500 N
600 N
700 N
Answer: 600 N