Answer:
a) Find the work done by the resistive force during the roundtrip.
W=-30kJ
b) Is the resistive force a conservative force? explain.
The resistive force is not a conservative force since the work done during the round trip is not zero
Explanation:
The worf done on object y a constant force F is given by:
W= (F cos ∅)S
Where S is the displacement and ∅ is the angle between the force and the displacement.
The displacement of the bicycle during each part of the trip is s=5000m and teh magnitude of teh resistance force is F=3.0N
∅1=180° he angle between the displacement and the force
W1=W2
W1 = (3.0 cos180) 5000m
W1=-15.O kJ
W=W1+W2
W=-30kJ
The resistive force is not a conservative force since the work done during the round trip is not zero
Answer:
P = m g v
Explanation:
Power is defined as the relationship between work and time
P = W / t
The work is defined by the scalar product of the force and the displacement, in the case of a drop falling the vertical force and the displacement has the same direction, therefore the angle between them is zero and the cosines of zero is one (cos 0 = 1)
W = F y
the gravitational force is proportional to the weight of the drop (F = mg)
W = mg y
we substitute
P = m g y / t
the terminal velocity of the drop is constant
P = m g v
