PHYSICS Flashcards
A man finds that he can walk 1 km in 20 min, 3 km in 1 hr, 6 km in 2 hr, and 9 km in 3 hr. These indicate that the distance he travels is:
(A) inversely proportional to the time
(B) inversely proportional to the square
of the time
(C) directly proportional to the time
(D) directly proportional to the square
of the time
C
What are the factors that determine the speed of a satellite which moves in a
stable orbit around a planet? (G represents the universal gravitational constant.)
(A) Mass of the planet and G
(B) Mass of the satellite and G
(C) Mass of the satellite, mass of the
planet, and G
(D) Orbital radius of the satellite, mass
of the planet, and G
D
A pingpong ball and a golf ball are dropped in a vacuum chamber from the
same height and at the same time. When they have fallen halfway, they
have the same
(A) potential energy
(B) kinetic energy
(C) acceleration
(D) velocity
D
A 10-pound object is suspended by a string from an overhead support. A horizontal force of 5.8 pounds is applied on the object. The measure of
the angle which the string makes with the horizontal is
(A) 30° (C) 60°
(B) 45° (D) 90°
C
A force of 60 newtons is used to raise a 240-newton load using a system of pulleys. The load covered a
distance of 1 m for every 5 m of rope pulled through the system. The system
has an efficiency of
(A) 12% (C) 60%
(B) 48% (D) 80%
D
Blocks C and D, weighing
4,000 newtons and 2,000 newtons, respectively, rest on a horizontal beam AB, as shown above. If the reaction produced at B is twice as great as the reaction produced at A, how far from A will the weight of Block C
act?
(A) 2 m (C) 3.5 m
(B) 3 m (D) 4.0 m
B
A body thrown vertically up into the air possesses kinetic energy at the beginning of its flight, but as it rises, it
loses kinetic energy and acquires potential energy with respect to the level
from which it started. Which of the following is NOT likely to happen?
(A) When it reaches the highest point, the kinetic energy has been wholly
changed to potential energy.
(B) As it falls, its potential energy is again transformed to kinetic
energy.
(C) The potential energy is maximum at the highest point of its flight.
(D) The kinetic energy is minimum at the lowest point of its flight.
D
Bernoulli’s principle states that A1V1 = A2V2. Blood flows from Artery A1, whose cross-sectional area is 50 µ2, at a velocity of 5 mm/s to its
more peripheral branches, A2, A3, A4, and A5. If the total cross-sectional area
of the branches is 250 µ2 and each branch has exactly the same diameter as the other, what is the velocity of
blood in the branches?
(A) 0.5 mm/s (C) 10.0 mm/s
(B) 1.0 mm/s (D) 25.0 mm/s
B
How much heat is required to warm 10 grams of ice from –10°C to 0°C?
(Specific heat of ice = 0.5 ° *Ccal/g )
(A) 75 cal (C) 25 cal
(B) 50 cal (D) 10 cal
B
ody X is in contact with Body Y which is hotter than Body X. Which of the following statements are true?
I. Body X gains heat and Body Y loses heat.
II. The temperature of Body X decreases and the temperature of Body Y increases.
III. The temperatures of Body X and Body Y will eventually be equal.
(A) I and II only
(B) I and III only
(C) II and III only
(D) I, II, and III
B
How many calories of heat is given off when 200 grams of water is cooled from 100°C to 20°C?
(A) 2,000 cal (C) 16,000 cal
(B) 4,000 cal (D) 20,000 cal
C
SPECIFIC HEAT OF WATER
4.19 J/gC or 1 cal/gC
BOILING HEAT OF WATER
100 C
A 1,200-watt heater is used for raising the temperature of 1 liter of water to boiling point. How long will it take for the water to boil if the initial temperature of water is 20°C? (1 cal = 4.19 joules)
(A) 28 s (C) 279 s
(B) 70 s (D) 349 s
C
If the absolute temperature of a gas is quadrupled and its pressure is halved, then the volume will
(A) increase four times
(B) increase eight times
(C) decrease four times
(D) decrease eight times
B
A glass flask which is partly filled with water is heated over a Bunsen flame. As soon as the water begins to boil, the flask is removed from the flame and tightly stoppered immediately. Boiling stops. When cold water is poured on the surface of the flask, which of the following will happen to the water inside the flask?
(A) It will begin to boil again since the contraction of the flask reduces the pressure inside.
(B) It will begin to boil again since the condensation of the steam reduces the pressure inside.
(C) It will not boil since the
temperature is less than 100°C.
(D) It will not boil since the contraction of the flask increases the pressure
inside.
B
A Carnot refrigerator takes heat from water at 0°C and rejects heat to a room at 27°C. If 50 kg of water at 0°C
is converted to ice at 0°C, how much energy must be supplied to the
refrigerator?
(A) 4.60 х 10–4 kWh
(B) 3.90 х 10–4 kWh
(C) 4.00 х 10–5 kWh
(D) 2.62 х 10–5 kWh
A
CARNOT EFFICIENCY
K= TC/ABSOLUTE TEMP which is Temp of hot - Temp of cold
The amount of heat required to raise the temperature of 10 grams of water at
10°C to 50°C is
(A) 100 cal (C) 500 cal
(B) 400 cal (D) 600 cal
B
The immediate source of water which forms dew on grass on a summer morning is the
(A) air
(B) soil
(C) grass
(D) cloud
A
A metal cube is heated over a Bunsen flame and then dropped into an insulated beaker containing water. The masses of the water, the beaker, and the cube, the initial and final temperatures of the water, and the specific heat capacities of the water and the beaker are known. Without further measurements, which of the following can be calculated?
(A) The density of the cube
(B) The specific heat capacity of the cube
(C) The thermal conductivity of the cube
(D) The specific latent heat of the cube
B
In hydroelectric plants, electric energy is generated by
(A) making the water evaporate
(B) distilling the water
(C) changing the water chemically
(D) making use of the power of a waterfall
D
A label of an electric stove reads “1,200 watts, 110 volts.” How much current will the appliance draw when it
is used?
(A) (1200) (110) amp
(B) (√1200) (110) amp
(C) 1200/110 amp
(D) (1200)/√(110)
C
OHM’S LAW
V=IR
