Physics Work and Power Flashcards
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Questions and Answers

What is the rate at which work is done?

  • Energy
  • Work
  • Power (correct)
  • Force

How much work is done to lift a 50kg barbell by 2m?

100J

Using a force to move an object through a distance is called what?

work

Is there work done on the wall?

<p>False (B)</p> Signup and view all the answers

If the distance is 20m and the force is 5000N, how much work will be done?

<p>100,000J</p> Signup and view all the answers

Mechanical energy combines what two types of energy?

<p>kinetic and gravitational potential energy</p> Signup and view all the answers

Kinetic energy is best described as what?

<p>the energy of motion</p> Signup and view all the answers

What is the formula for gravitational potential energy at a specific height?

<p>mgh</p> Signup and view all the answers

What cliff should the rock be thrown from to give it the greatest gravitational potential energy?

<p>4</p> Signup and view all the answers

How much power is produced when using 160J of energy in 8 seconds?

<p>20 W</p> Signup and view all the answers

Simple machines can increase the amount of work done.

<p>False (B)</p> Signup and view all the answers

What are the three classes of what?

<p>lever</p> Signup and view all the answers

When potential energy is converted to kinetic energy, some energy leaves the system due to what?

<p>friction</p> Signup and view all the answers

How much kinetic energy does a 2.0 kg ball have that is moving at 4 m/s?

<p>16 J</p> Signup and view all the answers

Reducing friction in a machine increases what?

<p>its efficiency</p> Signup and view all the answers

_____ is an example of a lever.

<p>mop</p> Signup and view all the answers

What law states that the total sum of mechanical energy in a closed system remains constant?

<p>Law of conservation of energy</p> Signup and view all the answers

What is the ideal mechanical advantage (IMA) for a ramp that is 6m long and 2 m high?

<p>3</p> Signup and view all the answers

What is the AMA when the reel on a fishing rod uses 4N of forces to pull up a 24N fish?

<p>6</p> Signup and view all the answers

The tire on a bicycle is an example of what?

<p>wheel and axle</p> Signup and view all the answers

Energy has the same unit as ___________, which is _____________.

<p>Work, Joules</p> Signup and view all the answers

The percentage of input work that is converted into output work is called what?

<p>Efficiency</p> Signup and view all the answers

Flashcards

What is power?

The rate at which work is done.

What is work?

The product of force and distance. It represents the energy transferred to an object when a force acts on it over a certain distance.

When is no work done?

No work is done on an object that is stationary, because there is no displacement.

What is mechanical energy?

The sum of kinetic energy and gravitational potential energy.

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What is gravitational potential energy?

The energy an object possesses due to its position relative to a reference point.

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What is kinetic energy?

The energy an object possesses due to its motion.

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How do simple machines affect work?

Simple machines don't increase the total work done, but they make it easier to perform.

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What is efficiency?

The ratio of useful work output to the total work input. It measures how efficiently a machine converts input energy into output energy.

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How does friction affect efficiency?

Reducing friction in machines increases their efficiency.

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What is the Law of Conservation of Energy?

The total mechanical energy in a closed system remains constant. Energy cannot be created or destroyed, only transferred or transformed.

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What are levers?

Tools designed to amplify force.

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What is ideal mechanical advantage?

The ratio of the distance moved by the effort force to the distance moved by the load force. It indicates how much the force is amplified.

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What is actual mechanical advantage?

The ratio of the output force to the input force. It quantifies the actual force amplification achieved.

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What is a wheel and axle?

A simple machine consisting of a wheel and an axle that rotate together. It amplifies the force applied.

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What is the unit of measurement for energy and work?

The unit of measurement for both energy and work.

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What is power output?

The rate at which energy is transferred or used, calculated by dividing energy by time.

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What is a ramp?

A ramp is a simple machine that reduces the force required to lift an object.

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How is the ideal mechanical advantage of a ramp calculated?

The ratio of the length of the ramp to the height of the ramp.

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What is effort force?

A force used to move a load.

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What is load force?

The force that is being moved by the effort force.

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How is the actual mechanical advantage of a system calculated?

The ratio of the load force to the effort force.

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Study Notes

Power and Work

  • Power is defined as the rate at which work is done.
  • Work done on an object is the product of force and distance; for instance, lifting a 50kg barbell 2m results in 100 Joules (J) of work.
  • Work is accomplished by applying a force to move an object over a certain distance.

Work and Force

  • No work is done on a stationary wall, as there is no displacement.
  • Calculating work: a force of 5000 Newtons (N) acting over a distance of 20 meters results in 100,000 Joules (J) of work.

Energy Types

  • Mechanical energy is the sum of kinetic energy (energy of motion) and gravitational potential energy.
  • Gravitational potential energy (PE) can be calculated using the formula PE = mgh, where m is mass, g is the acceleration due to gravity, and h is height.
  • Kinetic energy (KE) can be calculated for a moving object; for a 2.0 kg ball at 4 m/s, KE equals 16 J.

Efficiency and Machines

  • Simple machines do not increase the total amount of work done; rather, they make work easier.
  • Efficiency refers to the percentage of input work converted to output work, impacting the performance of machines.
  • Reducing friction in machines leads to increased efficiency.

Mechanical Systems

  • In a closed system, the total sum of mechanical energy remains constant, as stated by the Law of Conservation of Energy.
  • There are three classes of levers, which are tools that amplify force.
  • An example of a lever is a mop, which can change the direction of applied force.

Inverted Mechanical Advantage

  • The ideal mechanical advantage (IMA) for a ramp measuring 6m in length and 2m in height is 3.
  • For a fishing rod's reel that uses 4 N of force to pull a 24 N fish, the actual mechanical advantage (AMA) is calculated to be 6.

Structural Components

  • A tire is classified as a wheel and axle, demonstrating a simple machine.
  • The unit of energy is the same as that of work, both measured in Joules.

Power Calculation

  • Power output can be evaluated; using 160 Joules of energy in 8 seconds results in a power of 20 Watts (W).

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Test your knowledge on the concepts of work and power with these flashcards. Learn definitions, formulas, and practical applications related to force, distance, and energy. A great way to reinforce your understanding of physics principles.

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