Domanda del libro di testo
How much work must you do to push a 10 kg block of steel across a steel table at a steady speed of 1.0m/s for 3.0 s? What is your power output while doing so?
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Ch 09: Work and Kinetic Energy
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796
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TOC.tableOfContents
- Ch 01: Concepts of Motion35
- Ch 02: Kinematics in One Dimension75
- Ch 03: Vectors and Coordinate Systems58
- Ch 04: Kinematics in Two Dimensions60
- Ch 05: Force and Motion23
- Ch 06: Dynamics I: Motion Along a Line53
- Ch 07: Newton's Third Law27
- Ch 08: Dynamics II: Motion in a Plane52
- Ch 09: Work and Kinetic Energy56
- Ch 10: Interactions and Potential Energy50
- Ch 11: Impulse and Momentum56
- Ch 12: Rotation of a Rigid Body71
- Ch 13: Newton's Theory of Gravity52
- Ch 14: Fluids and Elasticity44
- Ch 15: Oscillations55
- Ch 16: Traveling Waves37
- Ch 17: Superposition39
- Ch 18: A Macroscopic Description of Matter53
- Ch 19: Work, Heat, and the First Law of Thermodynamics60
- Ch 20: The Micro/Macro Connection53
- Ch 21: Heat Engines and Refrigerators34
- Ch 22: Electric Charges and Forces40
- Ch 23: The Electric Field39
- Ch 24: Gauss' Law32
- Ch 25: The Electric Potential63
- Ch 26: Potential and Field57
- Ch 27: Current and Resistance42
- Ch 28: Fundamentals of Circuits39
- Ch 29: The Magnetic Field47
- Ch 30: Electromagnetic Induction60
- Ch 31: Electromagnetic Fields and Waves32
- Ch 32: AC Circuits63
- Ch 33: Wave Optics32
- Ch 34: Ray Optics57
- Ch 35: Optical Instruments30
- Ch 36: Special Relativity38
- Ch 37: The Foundations of Modern Physics25
- Ch 38: Quantization49
- Ch 39: Wave Functions and Uncertainty31
- Ch 40: One-Dimensional Quantum Mechanics35
- Ch 41: Atomic Physics18
- Ch 42: Nuclear Physics27
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796Non è quello che usi tu?Cambia libro di testo
Capitolo 9, Problema 37a
How much work does an elevator motor do to lift a 1000 kg elevator a height of 100 m?
Guida verificata passo dopo passo1
Identify the formula for work done: Work (W) is given by the equation , where is the force, is the displacement, and is the angle between the force and displacement vectors.
Determine the force required to lift the elevator: The force needed to lift the elevator is equal to its weight, which is calculated using , where is the mass of the elevator (1000 kg) and is the acceleration due to gravity (approximately 9.8 m/s²).
Substitute the values for force and displacement into the work formula: Since the force and displacement are in the same direction (upward), the angle is 0 degrees, and equals 1. The formula simplifies to .
Plug in the known values: Substitute kg, m/s², and m into the equation.
Simplify the expression to calculate the total work done: Perform the multiplication to find the work done by the elevator motor.
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Work
In physics, work is defined as the product of force and the distance over which that force is applied. It is calculated using the formula W = F × d, where W is work, F is the force applied, and d is the distance moved in the direction of the force. In the context of lifting an elevator, the force is equal to the weight of the elevator, which is the mass multiplied by the acceleration due to gravity.
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Percorso guidato
06:58
Calculating Net Work
Gravitational Force
Gravitational force is the attractive force between two masses, which on Earth is experienced as weight. It can be calculated using the formula F = m × g, where F is the gravitational force, m is the mass, and g is the acceleration due to gravity (approximately 9.81 m/s²). For the elevator, the gravitational force acting on it is crucial for determining the work done by the motor to lift it.
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05:41Gravitational Forces in 2D
Energy Conservation
The principle of energy conservation states that energy cannot be created or destroyed, only transformed from one form to another. In the case of the elevator, the electrical energy supplied to the motor is converted into mechanical energy to lift the elevator against the gravitational force. Understanding this principle helps in analyzing how much energy is required to perform the work of lifting the elevator.
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Percorso guidato
06:24Conservation Of Mechanical Energy
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