infinite, we’re actuallyrequiredto have an infinite positive kinetic energy in order to come up
with a total that conserves energy.
Answers
Answers for chapter 2
Page 126, problem 37:
K=k 1 k 2 /(k 1 +k 2 ) = 1/(1/k 1 + 1/k 2 )Answers for chapter 3
Page 222, problem 5:
After the collision it is moving at 1/3 of its initial speed, in the same direction it was initially
going (it “follows through”).
Page 229, problem 41:
Q= 1/
√
2
Page 229, problem 43:
(a) 7× 10 −^8 radians, or about 4× 10 −^6 degrees.
Page 231, problem 51:
(a)R= (2v^2 /g) sinθcosθ (c) 45◦
Page 231, problem 51:
(a)R= (2v^2 /g) sinθcosθ (c) 45◦
Page 231, problem 52:
(a) The optimal angle is about 40◦, and the resulting range is about 124 meters, which is about
the length of a home run. (b) It goes about 9 meters farther. For comparison with reality, the
stadium’s web site claims a home run goes about 11 meters farther there than in a sea-level
stadium.
Page 231, problem 52:
(a) The optimal angle is about 40◦, and the resulting range is about 124 meters, which is about
the length of a home run. (b) It goes about 9 meters farther. For comparison with reality, the
stadium’s web site claims a home run goes about 11 meters farther there than in a sea-level
stadium.
Answers for chapter 5
Page 348, problem 9:
(a)∼ 2 −10% (b) 5% (c) The high end for the body’s actual efficiency is higher than the limit
imposed by the laws of thermodynamics. However, the high end of the 1-5 watt range quoted in
the problem probably includes large people who aren’t just lying around. Still, it’s impressive
that the human body comes so close to the thermodynamic limit.
Page 349, problem 10:
(a) Looking up the relevant density for air, and converting everything to mks, we get a frequency
of 730 Hz. This is on the right order of magnitude, which is promising, considering the crudeness
of the approximation. (b) This brings the result down to 400 Hz, which is amazingly close to
the observed frequency of 300 Hz.
Answers for chapter 6