Podcast
Questions and Answers
For a force to do work on an object, what must some of the force do?
For a force to do work on an object, what must some of the force do?
Act in the same direction as the object moves
What is the equation for work?
What is the equation for work?
Work = force X distance
What is the equation for power?
What is the equation for power?
Power = work/time
One horsepower is equal to how many watts?
One horsepower is equal to how many watts?
Machines make work easier by changing what?
Machines make work easier by changing what?
What is the distance the input force acts through?
What is the distance the input force acts through?
You can increase the work input by increasing what?
You can increase the work input by increasing what?
What is the distance the output force is exerted through?
What is the distance the output force is exerted through?
What is the number of times that the machine increases an input force?
What is the number of times that the machine increases an input force?
What is determined by measuring the actual forces acting on a machine?
What is determined by measuring the actual forces acting on a machine?
What is the equation for actual mechanical advantage?
What is the equation for actual mechanical advantage?
What describes the mechanical advantage in the absence of friction?
What describes the mechanical advantage in the absence of friction?
What is the equation for ideal mechanical advantage?
What is the equation for ideal mechanical advantage?
What is the equation for efficiency?
What is the equation for efficiency?
Name the six simple machines.
Name the six simple machines.
What is a rigid bar that is free to move around a fixed point?
What is a rigid bar that is free to move around a fixed point?
What is the fixed point the bar rotates around?
What is the fixed point the bar rotates around?
What is the distance between the input force and the fulcrum?
What is the distance between the input force and the fulcrum?
What is the distance between the output force and the fulcrum?
What is the distance between the output force and the fulcrum?
Give an example of a first-class lever.
Give an example of a first-class lever.
A wheelbarrow is an example of what type of lever?
A wheelbarrow is an example of what type of lever?
The mechanical advantage of a first-class lever is always what?
The mechanical advantage of a first-class lever is always what?
The mechanical advantage of a second-class lever is always what?
The mechanical advantage of a second-class lever is always what?
The mechanical advantage of a third-class lever is always what?
The mechanical advantage of a third-class lever is always what?
Give an example of a third-class lever.
Give an example of a third-class lever.
A simple machine that consists of two disks or cylinders, each with a different radius.
A simple machine that consists of two disks or cylinders, each with a different radius.
Give an example of a wheel and axle.
Give an example of a wheel and axle.
What is a slanted surface along which a force moves an object to a different elevation?
What is a slanted surface along which a force moves an object to a different elevation?
A wheelchair ramp is an example of what?
A wheelchair ramp is an example of what?
Give an example of a wedge.
Give an example of a wedge.
Does a thin wedge or a thick wedge of the same length have a greater ideal mechanical advantage?
Does a thin wedge or a thick wedge of the same length have a greater ideal mechanical advantage?
Screws with threads that are closer or farther apart have a greater ideal mechanical advantage?
Screws with threads that are closer or farther apart have a greater ideal mechanical advantage?
A flagpole is an example of what type of pulley?
A flagpole is an example of what type of pulley?
A skyscraper window washer stands on a platform suspended by what type of a pulley?
A skyscraper window washer stands on a platform suspended by what type of a pulley?
What type of pulley is a combination of fixed and movable pulleys?
What type of pulley is a combination of fixed and movable pulleys?
A large crane lifting railroad locomotives is an example of what?
A large crane lifting railroad locomotives is an example of what?
How much work in N X m is done when a 10 N force moves an object 2.5 m?
How much work in N X m is done when a 10 N force moves an object 2.5 m?
If a machine has a mechanical advantage much larger than one, its output force is?
If a machine has a mechanical advantage much larger than one, its output force is?
How is the work output of a machine related to its work input?
How is the work output of a machine related to its work input?
A machine with 5 N input force and a 25 N output force has a mechanical advantage of?
A machine with 5 N input force and a 25 N output force has a mechanical advantage of?
The mechanical advantage of a pulley system depends upon?
The mechanical advantage of a pulley system depends upon?
If the output distance is 3 cm and the input distance is 15 cm, what is the ideal mechanical advantage?
If the output distance is 3 cm and the input distance is 15 cm, what is the ideal mechanical advantage?
If the output force is 50 N and the input force is 12.5 N, what is the actual mechanical advantage?
If the output force is 50 N and the input force is 12.5 N, what is the actual mechanical advantage?
What determines the class of a lever?
What determines the class of a lever?
A steel bolt, an iron nail, and a screwdriver are what type of simple machines?
A steel bolt, an iron nail, and a screwdriver are what type of simple machines?
If the actual mechanical advantage is 2.9 and the input force is 10 N, what is the output force?
If the actual mechanical advantage is 2.9 and the input force is 10 N, what is the output force?
How much work does a 50 N force do when lifting a box 2 meters?
How much work does a 50 N force do when lifting a box 2 meters?
How much work does a 1 kW motor do in one minute?
How much work does a 1 kW motor do in one minute?
What is the best way to increase power?
What is the best way to increase power?
When a machine does work, a trade off occurs. What best exemplifies the trade off?
When a machine does work, a trade off occurs. What best exemplifies the trade off?
A variation of an inclined plane is a?
A variation of an inclined plane is a?
Work input is greater than the work output when shooting a gun. Where does some of this go?
Work input is greater than the work output when shooting a gun. Where does some of this go?
A mechanical device requires 420 joules of work to do 230 joules of work lifting a crate. What is the efficiency?
A mechanical device requires 420 joules of work to do 230 joules of work lifting a crate. What is the efficiency?
Inclined planes reduce effort force by?
Inclined planes reduce effort force by?
How will a lubricant affect the efficiency of a simple machine such as a pulley?
How will a lubricant affect the efficiency of a simple machine such as a pulley?
If two swimmers compete in a race, does the faster one automatically develop more power?
If two swimmers compete in a race, does the faster one automatically develop more power?
A force of 11 N is applied to the handle of a screwdriver being used to pry off the lid of a paint can. As the input force moves through a distance of 0.3 m, the screwdriver does 3 joules of work on the lid. What is the efficiency?
A force of 11 N is applied to the handle of a screwdriver being used to pry off the lid of a paint can. As the input force moves through a distance of 0.3 m, the screwdriver does 3 joules of work on the lid. What is the efficiency?
Flashcards
Work
Work
Work occurs when a force acts in the same direction as the object moves.
Formula for Work
Formula for Work
Work is calculated as Work = Force × Distance.
Power
Power
Power is the rate at which work is done: Power = Work / Time.
Horsepower
Horsepower
Signup and view all the flashcards
Mechanical Advantage
Mechanical Advantage
Signup and view all the flashcards
Input Distance
Input Distance
Signup and view all the flashcards
Output Distance
Output Distance
Signup and view all the flashcards
Actual Mechanical Advantage
Actual Mechanical Advantage
Signup and view all the flashcards
Ideal Mechanical Advantage
Ideal Mechanical Advantage
Signup and view all the flashcards
Efficiency
Efficiency
Signup and view all the flashcards
Simple Machines
Simple Machines
Signup and view all the flashcards
Lever
Lever
Signup and view all the flashcards
First-Class Lever
First-Class Lever
Signup and view all the flashcards
Second-Class Lever
Second-Class Lever
Signup and view all the flashcards
Third-Class Lever
Third-Class Lever
Signup and view all the flashcards
Wheel and Axle
Wheel and Axle
Signup and view all the flashcards
Inclined Plane
Inclined Plane
Signup and view all the flashcards
Wedge
Wedge
Signup and view all the flashcards
Screws
Screws
Signup and view all the flashcards
Fixed Pulley
Fixed Pulley
Signup and view all the flashcards
Movable Pulley
Movable Pulley
Signup and view all the flashcards
Pulley System
Pulley System
Signup and view all the flashcards
Newton-meters
Newton-meters
Signup and view all the flashcards
Mechanical Advantage Ratio
Mechanical Advantage Ratio
Signup and view all the flashcards
Input vs Output Distance
Input vs Output Distance
Signup and view all the flashcards
Efficiency Factors
Efficiency Factors
Signup and view all the flashcards
Lubricants
Lubricants
Signup and view all the flashcards
Swimmer Competition
Swimmer Competition
Signup and view all the flashcards
Numerical Efficiency Assessment
Numerical Efficiency Assessment
Signup and view all the flashcards
Study Notes
Work, Power, and Machines
- Work occurs when a force acts in the same direction as the object moves.
- Formula for work: Work = Force × Distance.
- Power is defined as the rate at which work is done: Power = Work / Time.
- One horsepower is equivalent to 746 watts.
Mechanical Advantage
- Machines simplify work by altering the size, direction, or distance of a force.
- Input distance refers to the distance over which the input force acts.
- Increasing either the input distance or input force enhances work input.
- Output distance is the distance over which the output force is exerted.
- Mechanical advantage quantifies how much a machine amplifies an input force.
- Actual mechanical advantage is determined by the forces acting on the machine:
- Actual Mechanical Advantage = Output Force / Input Force.
- Ideal mechanical advantage is calculated without accounting for friction:
- Ideal Mechanical Advantage = Input Distance / Output Distance.
- Efficiency can be calculated using the formula: Efficiency = (Work Output / Work Input) × 100%.
Simple Machines
- The six types of simple machines include levers, wheels and axles, inclined planes, wedges, screws, and pulleys.
- A lever consists of a rigid bar that pivots around a fulcrum (fixed point).
- The input arm extends from the fulcrum to the input force, while the output arm extends from the fulcrum to the output force.
Lever Classes
- First-class levers have the fulcrum located between the input and output forces (e.g., seesaws, scissors).
- Second-class levers have the output force between the fulcrum and input force (e.g., wheelbarrows) and always have a mechanical advantage greater than 1.
- Third-class levers have the input force between the fulcrum and output force (e.g., baseball bats) and always have a mechanical advantage less than 1.
Other Simple Machines
- Wheel and axle systems consist of two disks or cylinders of different sizes (e.g., steering wheels, screwdrivers).
- Inclined planes provide a slanted surface to facilitate lifting (e.g., wheelchair ramps).
- Wedges are variations of inclined planes and include objects like knife blades.
- Screws feature closely spaced threads, providing a greater ideal mechanical advantage.
Pulleys
- Fixed pulleys change the direction of a force (e.g., flagpoles).
- Movable pulleys can lift heavier loads more easily (e.g., window washers).
- A pulley system combines fixed and movable pulleys for greater mechanical advantage.
Work and Efficiency Calculations
- Work done can be measured in Newton-meters (N × m).
- Relationships between input and output forces can be expressed as ratios indicating a machine's mechanical advantage.
- Input distance and output distance play key roles in calculating ideal mechanical advantage.
- Efficiency reflects the ratio of useful work done compared to total work input, often affected by factors such as friction and heat loss.
Practical Applications
- Lubricants can reduce friction, thereby enhancing a machine's efficiency.
- When two swimmers compete, more power can be generated by greater force, irrespective of their speed.
- The efficiency of mechanical devices can be assessed using specific numerical examples, revealing insights into work-loss during operation.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the concepts of work, power, and machines with these flashcards from Chapter 14 of your physics textbook. Each card presents key definitions and equations essential for understanding this fundamental topic in physics.
