Select T-True, F-False, for each statement. If the first is T and the rest F, en
ID: 1600466 • Letter: S
Question
Select T-True, F-False, for each statement. If the first is T and the rest F, enter TFFFFF.
A) The kinetic energy of a moving object is always positive.
B) Work can be done in the absence of motion.
C) The kinetic energy of an object is independent of the direction of the motion involved.
D) 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)
E) The work-energy principle is not valid if there are frictional forces acting.
F) The work done by a constant force acting on an object depends on the orientation of the force relative to the motion of the object
Explanation / Answer
A)True
KE = 1/2 m v^2
m is always positive and v^2 will always yeild a positive value.
B)False
W = F x d
So if the force does not displace an object work done is zero.
C)True
KE = 1/2 m v^2
v is the magnitude of velocity.
D)False
W = m g h
its independent of time
E)False
Its valid always and everywhere. The energy dissipated in work done against friction is always counted.
F)True
W = F d cos(theta)
So yes it depends on the orientation.
Ans: TFTFFT