4.[1pt] Select T-True, F-False, for each statement. If the first is T and the re

Question

4.[1pt] Select T-True, F-False, for each statement. If the first is T and the rest F, enter TFFFFF. A) Work cannot be done in the absence of motion. B) The kinetic energy can never be negative. C) The work-energy principle is perfectly valid even when there are frictional forces acting D) The kinetic energy of an object depends on the direction of the motion involved. E) 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) 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 Answer: Submit All Answers 5.[1pt] A constant force of 59.1 N, directed at 27.5° from horizontal, pulls a mass of 13.1 kg horizontally a distance of 2.69 m. Calculate the work done by the force. Answer Submit All Answers

Explanation / Answer

A) True

because, W = F*d*cos(theta)

if s = 0, W = 0

B) True

Because, KE = (1/2)*m*v^2

C) True

Net workdone = change in kinetic energy

D) False

E) False

It depends only on height raised but not how fat it is raised.

F) True

because, W = F*s*cos(theta)

As theta changes W also changes

5)

given

F = 59.1 N
theta = 27.5 degrees

m = 13.1 kg

s = 2.69

Workdone = F*s*cos(theta)

= 59.1*2.69*cos(27.5)

= 141 J

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