# Elevator problem: energy, power, intensity,

• Jack Brodie
In summary, the conversation discusses calculating the energy, time, and power required to lift an elevator and its load to a height of 100m. The energy is found using the formula E=MgL, and the power can be calculated using P=E/t. The intensity can also be determined using the formula I=P/A. The correct answers for the given values are 1176000 Joules for energy, 20 seconds for time, and 58.5 watts for power.

## Homework Statement

Question: An Elevator and its load have a mass of 1200 kg.
a) what energy must be supplied to lif the elevator and its load ot a height of 100m? Answer: E = _________ Joules

b)If the elevator rises at a speed of 5 m/s, how long does it take to cover 100m? Answer t= __________ sec

c) What is the power supplied? Answer P = ________ Watts

## Homework Equations

Energy: E=MgL, where g=9.8m/s2 (squared) is the acceleration of gravity and Lis the distance through which a mass is moved against the force of gravity
Power: P = E/t
Intensity: I= P/A

## The Attempt at a Solution

For part a, I used the first equation (E=MgL) and I got the answer of 1176 Joules

part b: at a rate of 5 m/s it would take 20 seconds; so t = 20 seconds

Part c: P=E/t is P= 1176/20 = 58.5 watts

Does this seem right?

The answer to the first one should be 1176000 Joules, but your formulas are correct.

Thank you for taking time to help! I appreciate it!

## 1. What is the energy used by an elevator?

The energy used by an elevator is dependent on several factors such as the weight of the elevator, the height it needs to travel, and the speed at which it travels. It can range from 1-10 kilowatts per hour.

## 2. How is the power of an elevator calculated?

The power of an elevator is calculated by multiplying the force required to move the elevator by the speed at which it travels. This is typically measured in watts or kilowatts.

## 3. What role does intensity play in the elevator problem?

Intensity is not a major factor in the elevator problem. It is more commonly used in the context of sound or light waves. In elevators, power and energy are the main measurements used to understand the operation of the elevator.

## 4. How does the weight of the elevator affect its energy consumption?

The weight of the elevator plays a significant role in its energy consumption. A heavier elevator will require more energy to move compared to a lighter one. This is why elevators are designed to be as lightweight as possible while still being able to carry the desired weight capacity.

## 5. Is it more energy-efficient for an elevator to move at a constant speed or to accelerate and decelerate?

It is more energy-efficient for an elevator to move at a constant speed. Accelerating and decelerating require more energy as the elevator needs to overcome inertia and friction. This is why modern elevators are designed with efficient motor systems to maintain a steady speed throughout the ride.