Hi, I only have 1 chance to get this right. Correct me pls.
A) The kinetic energy of an object depends on the direction of the motion involved.
False, KE=1/2mv^2, the ^2 cancels any +/- involved in vectors.
B) The kinetic energy can never be negative.
False, same reasoning as above.
C) The work done by a constant force acting on an object is independent of the orientation of the force relative to the motion of the object
False, if an object's force opposes, the motion, the work done is negative??? not sure
D) The work-energy principle is not valid if there are frictional forces acting.
True, friction is converted into heat and the system KE=PE, so the sys loses energy
E) Work cannot be done in the absence of motion.
False, W=fd, and if d=0, then W=0
F) The work done to raise a box onto a platform depends on how fast it is raised. (Neglect friction, assume it starts on the ground at rest, and ends up resting on the platform)
False, because it
2006-10-21
00:33:46
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7 answers
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asked by
JustWondering
1