Work
-Work: The product of force and distance.
-Work requires motion.
-For a force to do work on an object, some of the force must act in the same direction as the object moves. If there is no movement, no work is done.
-Work depends on direction.
-The amount of work done on an object, if any, depends on the direction of te force and the direction of the movement.
-A force does not have to entirely in the direction of movement to do work.
-Any part of a force that does not act in the direction of motion does no work on an object.
-Work = Force x Distance
-The unit for work is the Joule (J).
-A joule is when a force of one newton moves an object one meter in the direction of the force.
Power
-Power: The rate of doing work.
-Doing work at a faster rate requires more power. To increase power, you can increase the amount of work done in a given time, or you can do a given amount of work in less time.
-Power = Work / Time
-The SI unit for power is watt (w).
-Along with watt, another common unit is horsepower (hp).
-One horsepower is equal to 746 watts.
-Work: The product of force and distance.
-Work requires motion.
-For a force to do work on an object, some of the force must act in the same direction as the object moves. If there is no movement, no work is done.
-Work depends on direction.
-The amount of work done on an object, if any, depends on the direction of te force and the direction of the movement.
-A force does not have to entirely in the direction of movement to do work.
-Any part of a force that does not act in the direction of motion does no work on an object.
-Work = Force x Distance
-The unit for work is the Joule (J).
-A joule is when a force of one newton moves an object one meter in the direction of the force.
Power
-Power: The rate of doing work.
-Doing work at a faster rate requires more power. To increase power, you can increase the amount of work done in a given time, or you can do a given amount of work in less time.
-Power = Work / Time
-The SI unit for power is watt (w).
-Along with watt, another common unit is horsepower (hp).
-One horsepower is equal to 746 watts.
Machines
-There are six types of simple machines.
-Levers: A rigid bar that is free to move around a fixed point.
-The fixed point the bar rotates around is the fulcrum.
-Levers are classified into three categories based on the locations of the input force, output force, and the fulcrum.
-The input arm of a lever is the distance between the input force and the fulcrum.
-The output arm is the distance between the output force and the fulcrum.
-To calculate the ideal mechanical advantage of any lever, divide input arm by output arm.
-First class levers: The fulcrum of a first class lever is always between the input force and the output force.
-Second class levers: The output force is always located between the input force and the fulcrum.
-Third- class levers: The input force is always located between the fulcrum and the output force.
-Wheel and Axle: Two disks or cylinders, each one a different radius. Such as a steering wheel.
-The outer disk is the wheel and the inner disk is the axle.
-To calculate the ideal mechanical advantage of the wheel and axle, divide the radius ( or diameter) where the input force is exerted by the radius where the output force is exerted.
-Inclined Planes: A slanted surface along which a force moves an object to a different elevation.
-Think of a windy road up a mountain.
-The ideal mechanical advantage of an inclined plane is the distance along the inclined plane divided by its change in height.
-Wedges and Screws:
-Wedge: a V-shaped object who's sides are two inclined planes sloped together toward each other.
-A thin wedge of a given length has a greater mechanical advantage than a thick wedge of the same length.
-Screws: An inclined plane wrapped around a cylinder.
-Screws with threads that are closer together have a greater ideal mechanical advantage.
-Pulleys: A simple machine that consists of rope that fits into a groove in a wheel.
-Fixed pulleys: A wheel attached in a fixed location. They are only able to rotate in one place. For example, the pulley at the top of a flag pole, or the pulley used to pull up blinds.
-Movable Pulley: Attached to an object being moved rather than in a fixed location. For example the pulleys used to lift sails, and skyscraper window washers.
-Pulley System: Combining fixed and moveable pulleys creates a pulley system. For example, large cranes.
-There are six types of simple machines.
-Levers: A rigid bar that is free to move around a fixed point.
-The fixed point the bar rotates around is the fulcrum.
-Levers are classified into three categories based on the locations of the input force, output force, and the fulcrum.
-The input arm of a lever is the distance between the input force and the fulcrum.
-The output arm is the distance between the output force and the fulcrum.
-To calculate the ideal mechanical advantage of any lever, divide input arm by output arm.
-First class levers: The fulcrum of a first class lever is always between the input force and the output force.
-Second class levers: The output force is always located between the input force and the fulcrum.
-Third- class levers: The input force is always located between the fulcrum and the output force.
-Wheel and Axle: Two disks or cylinders, each one a different radius. Such as a steering wheel.
-The outer disk is the wheel and the inner disk is the axle.
-To calculate the ideal mechanical advantage of the wheel and axle, divide the radius ( or diameter) where the input force is exerted by the radius where the output force is exerted.
-Inclined Planes: A slanted surface along which a force moves an object to a different elevation.
-Think of a windy road up a mountain.
-The ideal mechanical advantage of an inclined plane is the distance along the inclined plane divided by its change in height.
-Wedges and Screws:
-Wedge: a V-shaped object who's sides are two inclined planes sloped together toward each other.
-A thin wedge of a given length has a greater mechanical advantage than a thick wedge of the same length.
-Screws: An inclined plane wrapped around a cylinder.
-Screws with threads that are closer together have a greater ideal mechanical advantage.
-Pulleys: A simple machine that consists of rope that fits into a groove in a wheel.
-Fixed pulleys: A wheel attached in a fixed location. They are only able to rotate in one place. For example, the pulley at the top of a flag pole, or the pulley used to pull up blinds.
-Movable Pulley: Attached to an object being moved rather than in a fixed location. For example the pulleys used to lift sails, and skyscraper window washers.
-Pulley System: Combining fixed and moveable pulleys creates a pulley system. For example, large cranes.
-Compound Machines: A combination of two or more simple machines that operate together. For example: A car, a watch, and a clock.
Questions
1.What does work require? (see student solutions)
2. What is the SI unit for power? (see student solutions)
3. Give an example of an inclined plane.
4. Give an example of a pulley system.
Questions
1.What does work require? (see student solutions)
2. What is the SI unit for power? (see student solutions)
3. Give an example of an inclined plane.
4. Give an example of a pulley system.
The light bulb application is the machines. Every machine listed on there is important to the things we have/ use. Our cars are compound machines. We could not transport things without pulley systems. Things we do in every day life require us to use those simple machines.