a. acts vertically on a cart that can move only horizontally
b. is exerted by one team in a tug of war when there is no movement
c. is exerted on a wagon while pulling it up a hill
d. of gravitational attraction acts on a person standing on the surface of Earth
2007-04-01 13:09:12 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
c; only sure indication of motion. In others force(s) may be acting, but work needs displacement.
A. force acts perpendicular to displacement direction, which means cos(theta) = cos(90) = 0
B. NO MOVEMENT = NO DISPLACEMENT = NO WORK DONE
D. The person is STANDING; no sure sign of movement happening.
2007-04-01 13:12:11 · answer #1 · answered by J Z 4 · 0⤊ 0⤋
Work requires movement. Otherwise there is no work, so your first 2 answers and the last one fall away.
Clearly pulling a wagon is work, as long as the wagon is moving
2007-04-01 20:13:48 · answer #2 · answered by reb1240 7 · 0⤊ 0⤋
a
2007-04-05 16:42:47 · answer #3 · answered by schntae b 1 · 0⤊ 0⤋