Semester: March – June 2014

Course: PHY440 Mechanics, Waves and Thermal Physics

Text book: Jewett, J.W. and Serway, R.A. (2010). Physics for Scientists and Engineers with Modern Physics, 8th Edition, Brooks/Cole Cengage Learning.

Assignment 4

Question / Topic / Problem
1 / Section 14.2 Variation of Pressure with Depth / No 8 (Softcopy) p.424; No 8 (Hardcopy) p. 424
The small piston of a hydraulic lift (Fig. P14.8) has a crosssectional
area of 3.00 cm2, and its large piston has a crosssectional
area of 200 cm2. What downward force of magnitude
F1 must be applied to the small piston for the lift to
raise a load whose weight is Fg = 15.0 kN?
2 / Section 14.4 Buoyant Forces and Archimedes’s Principle / No 31 (Softcopy) p.426; No 33 (Hardcopy) p. 426
31. A wooden block of volume 5.24 ´ 10-4 m3 floats in
water, and a small steel object of mass m is placed on top of
the block. When m = 0.310 kg, the system is in equilibrium
and the top of the wooden block is at the level of the water.
(a) What is the density of the wood? (b) What happens to
the block when the steel object is replaced by an object
whose mass is less than 0.310 kg? (c) What happens to the
block when the steel object is replaced by an object whose
mass is greater than 0.310 kg?
3 / Section 14.6 Bernoulli’s Equation / No 37 (Softcopy) p.427; No 37 (Hardcopy) p. 426
37. A large storage tank, open at the top and filled with water,
develops a small hole in its side at a point 16.0 m below the
water level. The rate of flow from the leak is found to be
2.50 ´ 10-3 m3/min. Determine (a) the speed at which the
water leaves the hole and (b) the diameter of the hole.
4 / Section 14.4 Buoyant Forces and Archimedes’s Principle / No 62 (Softcopy) p.430; No 64 (Hardcopy) p. 430
62. A 42.0-kg boy uses a solid block of Styrofoam as a raft while
fishing on a pond. The Styrofoam has an area of 1.00 m2 and is 0.0500 m thick. While sitting on the surface of the raft, the boy finds that the raft just supports him so that the top of the raft is at the level of the pond. Determine the density of the Styrofoam.
5 / Section 16.3 The Speed of Waves on Strings / No 23 (Softcopy) p.484; No 23 (Hardcopy) p. 484
23. Transverse waves travel with a speed of 20.0 m/s on a
string under a tension of 6.00 N. What tension is required
for a wave speed of 30.0 m/s on the same string?
6 / Section 16.3 The Speed of Waves on Strings / No 26 (Softcopy) p.484; No 28 (Hardcopy) p. 484
26. A transverse traveling wave on a taut wire has an amplitude
of 0.200 mm and a frequency of 500 Hz. It travels with a
speed of 196 m/s. (a) Write an equation in SI units of the
form y = A sin (kx - wt) for this wave. (b) The mass per
unit length of this wire is 4.10 g/m. Find the tension in the
wire.
7 / Section 20.2 Specific Heat and Calorimetry / No 2 (Softcopy) p.592; No 6 (Hardcopy) p. 592
2. The highest waterfall in the world is the Salto Angel Falls
in Venezuela. Its longest single falls has a height of 807 m. If water at the top of the falls is at 15.0°C, what is the maximum temperature of the water at the bottom of the falls? Assume all the kinetic energy of the water as it reaches the bottom goes into raising its temperature.
8 / Section 20.3 Latent Heat / No 17 (Softcopy) p.593; No 19 (Hardcopy) p. 594
17. Steam at 100°C is added to ice at 0°C. (a) Find the amount
of ice melted and the final temperature when the mass of steam is 10.0 g and the mass of ice is 50.0 g. (b) What If? Repeat when the mass of steam is 1.00 g and the mass of ice is 50.0 g.
9 / Section 20.5 The First Law of Thermodynamics / No 30 (Softcopy) p.594; No 30 (Hardcopy) p. 594
30. A sample of an ideal gas goes through the process shown
in Figure P20.30. From A to B, the process is adiabatic;
from B to C, it is isobaric with 100 kJ of energy entering
the system by heat; from C to D, the process is isothermal;
and from D to A, it is isobaric with 150 kJ of energy leaving
the system by heat. Determine the difference in internal
energy Eint,B - Eint,A.
10 / Section 20.6 Some Applications of the First Law
of Thermodynamics / No 33 (Softcopy) p.595; No 31 (Hardcopy) p. 594
33. A 2.00-mol sample of helium gas initially at 300 K, and
0.400 atm is compressed isothermally to 1.20 atm. Noting that the helium behaves as an ideal gas, find (a) the final volume of the gas, (b) the work done on the gas, and (c) the energy transferred by heat.

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