Answer: [tex]P=5573.43\ W[/tex]
Explanation:
Given
Mass of the elevator is [tex]M=650\ kg\\\[/tex]
Time period of ascension [tex]t=3\ s[/tex]
cruising speed [tex]v=1.75\ m/s[/tex]
Distance moved by elevator during this time
Suppose Elevator starts from rest
[tex]\Rightarrow v=u+at\\\Rightarrow 1.75=0+a(3)\\\Rightarrow a=0.583\ s[/tex]
Distance moved
[tex]\Rightarrow h=ut+0.5at^2\\\Rightarrow h=0+0.5\times 0.5833\times (3)^2\\\Rightarrow h=2.62\ m[/tex]
Gain in Potential Energy is
[tex]\Rightarrow E=mgh\\\Rightarrow E=650\times 9.8\times 2.62\\\Rightarrow E=16,720.3\ N[/tex]
Average power during this period is
[tex]\Rightarrow P=\dfrac{E}{t}\\\\\Rightarrow P=\dfrac{16,720.3}{3}\\\\\Rightarrow P=5573.43\ W[/tex]
Answer:
The power is 331.7 W.
Explanation:
mass, m = 650 kg
time, t= 3 s
initial velocity, u = 0 m/s
final velocity, v = 1.75 m/s
(a) The power is defined as the rate of doing work.
Work is given by the change in kinetic energy.
W = 0.5 m (V^2 - u^2)
W = 0.5 x 650 x 1.75 x 1.75 = 995.3 J
The power is given by
P = W/t = 995.3/3 = 331.7 W
