Answer: v = 0.8786m/s W = 79.54J
Explanation: The blank space asks for the velocity of the elevator. Velocity is defined by the space an object moves per time it needs to travel this space. In other words: v = Δs / Δt.
According to the question, the elevator go through 2.75m in 3.13s, so velocity will be
v = [tex]\frac{2.75}{3.13}[/tex] = 0.8786 m/s. This is the cruising speed.
Power is the amount of work done by an object per period of time.
W = τ / Δt
In this case, the work (τ) is due to the movement of the elevator. Using the work-energy theorem, which states that the amount of work done in a moving object can be determined by the variation of its kinetic energy, power can be rewritten as:
W = ([tex]\frac{m.v^{2} }{2} - \frac{m.v0^{2} }{2}[/tex]) / Δt
As the elevator starts from rest, the initial velocity is 0.
W = ([tex]\frac{645.0.8786^{2} }{2}[/tex]) / 3.13
W = 79.54 J
The average power delivered by the motor is 79.54J.
