# Physics Homework

homework 12 –

Question 1, chap 119, sect 4.

part 1 of 1 10 points

Convert Kelvin temperature 2000 K to Cel- sius. Answer in units of ◦C.

Question 2, chap 119, sect 5.

part 1 of 2 10 points

At 32◦C, an aluminum ring has an inner di- ameter of 6 cm and a brass rod has a diameter of 6.01 cm. If the temperature coefficient of expansion

for brass is αb = 1.9× 10 −5 (◦C)−1 and the

temperature coefficient of expansion for alu- minum is αa = 2.4× 10

−5 (◦C)−1, to what temperature must the ring be heated so that it will just slip over the rod? Answer in units of ◦C.

Question 3, chap 119, sect 5.

part 2 of 2 10 points

To what temperature must both be heated so that the ring just slips over the rod? Answer in units of ◦C.

Question 4, chap 119, sect 5.

part 1 of 1 10 points

A 27 gallon steel container is completely filled with carbon tetrachloride. Its temper- ature is 7 ◦C. The average volume coeffi- cient of expansion for carbon tetrachloride is 0.000581(◦C)−1. How much carbon tetrachloride will spill

over when the temperature rises to 26◦C? As- sume that the steel container is held at con- stant temperature so that its volume remains constant. Answer in units of gal.

Question 5, chap 119, sect 5.

part 1 of 1 10 points

A square hole 10.5 cm along each side is cut in a sheet of copper. Calculate the change in the area of this hole

if the temperature of the sheet is increased by 26 K. The coefficient of linear expansion of copper is 1.7× 10−5 (◦C)−1. Answer in units of cm2.

Question 6, chap 119, sect 5.

part 1 of 2 10 points

A pendulum clock with a brass suspension system is calibrated so that its period is 1 s at 8◦C. If the temperature increases to 44 ◦C, by

how much does the period change? Answer in units of s.

Question 7, chap 119, sect 5.

part 2 of 2 10 points

How much time does the clock gain or lose in one week? Answer in units of s.

Question 8, chap 119, sect 5.

part 1 of 1 10 points

A car has a 31 L steel gas tank filled to the top with gasoline when the temperature is 8◦C. Assume the linear expansion coefficient for steel is 1.1× 10−5 K−1 and the volume expansion of gasoline is 0.0009 K−1. Taking the expansion of the steel tank into

account, how much gasoline spills out of the tank when the car is parked in the sun and its temperature rises to 45◦C? Answer in units of L.

Question 9, chap 119, sect 7.

part 1 of 2 10 points

An air bubble originating from an under- water diver has a radius of 6 mm at some depth h. When the bubble reaches the surface of the water, it has a radius of 7.1 mm. The acceleration of gravity is 9.8 m/s2 . Assuming the temperature of the air in the

bubble remains constant, determine the depth of the diver. Answer in units of m.

Question 10, chap 119, sect 7.

homework 12 – ALGHAMDI, ALI – Due: Nov 18 2017, 11:00 pm (Central time) 2

part 2 of 2 10 points

Determine the absolute pressure at this depth. Answer in units of kPa.

Question 11, chap 119, sect 7.

part 1 of 1 10 points

A cylinder with a movable piston contains gas at a temperature of 34.9◦C, a volume of 2 m3, and an absolute pressure of 20400 Pa. What will be its final temperature if the

gas is compressed to 0.57 m3 and the absolute pressure increases to 86837 Pa? Answer in units of ◦C.

Question 12, chap 119, sect 7.

part 1 of 1 10 points

An auditorium is 9 m high, 41 m long, and 20 m wide. How many molecules of air are needed to

fill the auditorium at 32◦C and 99.9 kPa pres- sure? The gas constant is 8.31 J/K ·mol.

Question 13, chap 120, sect 2.

part 1 of 1 10 points

A 2 kg block of ice at a temperature of 0.0◦C and an initial speed of 6.9 m/s slides across a level floor. If 330000 J are required to melt 1 kg of

ice, how much ice melts, assuming that the initial kinetic energy of the ice block is entirely converted to the ice’s internal energy? Answer in units of kg.

Question 14, chap 120, sect 3.

part 1 of 1 10 points

A 755 kg car moving at 24 m/s brakes to a stop. The brakes contain about 14 kg of iron that absorb the energy. What is increase in temperature of the

brakes? Assume the specific heat of iron is 450 J/kg ·◦ C. Answer in units of ◦C.

Question 15, chap 120, sect 5.

part 1 of 1 10 points

A 4.9 g lead bullet moving at 278 m/s strikes a steel plate and stops. If all its kinetic energy is converted to ther-

mal energy and none leaves the bullet, what is its temperature change? Assume the specific heat of lead is 128 J/kg/◦C. Answer in units of ◦C.

Question 16, chap 120, sect 6.

part 1 of 1 10 points

A 0.013 g cube of ice at 0◦C is added to 0.442 g of soup at 81.1◦C. The specific heat of water is 4186 J/kg ·◦C

and the latent heat of fusion for water is 333000 J/kg. Assuming that the soup has the same spe-

cific heat capacity as water, find the final tem- perature of the soup after the ice has melted. Answer in units of ◦C.

Question 17, chap 120, sect 6.

part 1 of 1 10 points

At a foundry, 24 kg of molten aluminum with a temperature of 660.4◦C is poured into a mold. The specific heat of aluminum is

899 J/kg ·◦C and its latent heat of fusion is 397000 J/kg. If this is carried out in a room containing

140 kg of air at 25◦C, what is the temperature of the air after the aluminum is completely solidified? Assume that the specific heat ca- pacity of air is 1000 J/kg ·◦C and that the melting point of aluminum is 660.4◦C. Answer in units of ◦C. 