Physics 103 : Practice Final
1) Two dams are identical with the exception that the water reservoir behind dam A extends twice the horizontal distance behind it as that of dam B. Which one of the following statements regarding these dams is correct?
a) The force exerted by the water on dam A is greater than that on dam B.
b) The force exerted by the water on dam B is greater than that on dam A.
c) Dam A is more likely to collapse than dam B if the water level rises.
d) Dam B is more likely to collapse than dam A if the water level rises.
e) The horizontal distance of the water behind the two dams does not determine the force on them.
2) Using the value of atmospheric pressure at sea level, 1 x 105 Pa, estimate the total mass of the earth's atmosphere above a 5-m2 area.
a) 5 x 104 kg
b) 9 x 104 kg
c) 2 x 104 kg
d) 4 x 10-2 kg
e) 5 x 105 kg
3) Temperature of an ideal gas contained in a box is decreased:
a) the average velocity of the molecules in the box will be decreased.
b) the number ofmolecules in the box will be increased
c) the average energy of the molecules in the box will be increased.
d) the distance between molecules in the box will be increased.
e) the average time between collisions will be increased.
4) A hydraulic lift is used to lift a block of mass M. The block rests on the right massless plunger. A force F1 is applied to the left massless plunger. The two plungers are at the same height. The diameter of the left cylinder is D1 and the diameter of the right cylinder is D2. What force F1 is required to lift the block?
(a)Mg
(b)Mg(D1/D2)
(c)Mg(D2/D1)
(d)Mg(D1/D2)2
(e)Mg(D2/D1)2
5) Internal energy of a gas has been used to accomplish some work. Which of the following properties of the gas has definitely changed?
a) pressure
b) volume
c) temperature
d) specific heat
e) chemical composition