You lift a book with your hand in such a way that it moves up at constant speed. While it is moving, what is the total work done on the book?
a) mg × ?r
b) FHAND × ?r
c) (FHAND + mg) × ?r
d) zero
e) none of the above
Ans: d) zero
You might also like to view...
Which statement best describes the greenhouse effect? a. infrared radiation escapes into space
b. ultraviolet radiation enters a planet's atmosphere producing a green haze c. visible radiation is trapped by the atmosphere. d. infrared radiation is trapped by the atmosphere. e. oxygen escapes from the atmosphere.
If a fish looks upward at 45° to a pond's water's surface, it will see
A) the pond's bottom. B) the sky and possibly some tall surroundings. C) only the water's surface. D) none of the above
When one note is above another note by an octave, the frequency of the higher pitch note is double that of the lower pitch note. The word octave may make you think that there are 8 steps from the lower note to the one an octave above. But wait! How many steps are there on a piano from middle C to the next C above? Each key is a step. If each next key is a step, how many are there? Middle C is a
white (W) key and the next note above is a black (B) key. Starting at middle C on the piano the sequence of key we go through to get to high C, is BWBWWBWBWBWW, the last key being high C. Count ‘em. That's 12 steps. If the multiplying factor of the frequency for the next step is the same for each step, what is that multiplying frequency? All you need is given in this problem statement. a. 101/12 b. 121/8 c. 21/8 d. 21/12
A key clue to how the solar system formed is the observation that all the planets orbit close to the same plane
Indicate whether the statement is true or false