Physics for the Utterly Confused

Errata Sheet for the first printing

Pg. 6

The x and y are scrambled in the sentence just opposite the Watch Out icon. The sentence should read:

Notice that the angle q in the diagram is taken with respect to the x axis while f was taken with respect to the y axis.

Pg. 14

In problem 2-3, the second time is 104.8 seconds, not 59.8 seconds.

In problem 2-4 Galileo is initially reported as dropping the ball from 120 m. It should be 150 m. The 150 m number is used through the remainder of the problem.

Pg. 23

The equations for the velocity should be:

The total time of flight is then 2´17.6 = 35.2 seconds.

The horizontal distance traveled in this time is:

x = (41.0 m/s)(35.2 sec) = 1443 meters Þ 0.90 miles

Pg. 31

In the statement of the problem the angle should be written as 33^o, as it is in the rest of the problem.

Pg. 36

The x center of gravity is 0.93, not 1.15. Change the equation for the x center of gravity and in the third line of text.

Pg. 37

The x center of gravity is 0.365 m, not 1.18 m.

The y center of gravity is 0.844 m, not 1.03 m.

Pg. 50

In the middle of the page the equations should read:

Force_friction = 0.25(3.0 kg)(9.8 m/s²)(cos 58^o) = 3.89 N

The work done to overcome friction is (3.89 N)(4.0 m) = 15.6 J

Now we can plug this into the original energy equation and solve for velocity.

99.7 J = (1/2)mv² + 15.6 J Þ v = [(84.1 J)(2)(3.0 kg)]^1/2 = 56.1 m/s

Also toward the bottom of the page the bold type should read “. . . the correct answer is 7.49 m/s.”

Pg. 176 There is a typo in problem 25-6. The word “also” is typed “alos.”