In 2 minutes, a ski lift raises four skiers at a constant speed to a height of 123 m. The average mass of each skier is 71 kg. W
1 answer:
Answer:
The average power provided by the tension in the cable pulling the lift is = 714 W
Explanation:
Given data
Mass = 71 kg
Change in height = 123 m
When the lift moves in upward direction then in that case kinetic energy is constant & only potential energy changes.
Change in potential energy Δ PE = m g ( )
Δ PE = 71 × 9.81 × 123
Δ PE = 85670.73 J
Time = 2 min = 120 sec
So average power is given by
Therefore the average power provided by the tension in the cable pulling the lift is = 714 W
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Answer:
v = 5.34[m/s]
Explanation:
In order to solve this problem, we must use the theorem of work and energy conservation. This theorem tells us that the sum of the mechanical energy in the initial state plus the work on or performed by a body must be equal to the mechanical energy in the final state.
Mechanical energy is defined as the sum of energies, kinetic, potential, and elastic.
E₁ = mechanical energy at initial state [J]
In the initial state, we only have kinetic energy, potential energy is not had since the reference point is taken below 1.5[m], and the reference point is taken as potential energy equal to zero.
In the final state, you have kinetic energy and potential since the car has climbed 1.5[m] of the hill. Elastic energy is not available since there are no springs.
E₂ = mechanical energy at final state [J]
Now we can use the first statement to get the first equation:
where:
W₁₋₂ = work from the state 1 to 2.
where:
h = elevation = 1.5 [m]
g = gravity acceleration = 9.81 [m/s²]