Work
In science, the definition of work is very different than how we use the word every day. Work is when an applied force makes an object move in the same direction as the applied force. For example, let's say you were moving your lawn with your new lawn mower. You would be doing work because the force you applied to the lawn mover to make it move forward and the resulting motion are in the same direction. A weightlifter named Bob lifting a barbell over his head would also be an example of work being done. Bob applies force to the barbell to make it go up and over his head and the barbell moves up. The amount of work done is dependent on how much force is applied and the distance across which the force is applied. The equation for work is Work = Force× Distance. Work is measured in Joules (J), force is measured in Newtons (N), and distance is measured in meters (M).
In science, the definition of work is very different than how we use the word every day. Work is when an applied force makes an object move in the same direction as the applied force. For example, let's say you were moving your lawn with your new lawn mower. You would be doing work because the force you applied to the lawn mover to make it move forward and the resulting motion are in the same direction. A weightlifter named Bob lifting a barbell over his head would also be an example of work being done. Bob applies force to the barbell to make it go up and over his head and the barbell moves up. The amount of work done is dependent on how much force is applied and the distance across which the force is applied. The equation for work is Work = Force× Distance. Work is measured in Joules (J), force is measured in Newtons (N), and distance is measured in meters (M).
Simple Machines
Simple machines are any of several devices with few or no moving parts that are used to modify motion and force in order to perform work. Machines are anything that makes work easier so even a ramp is considered a simple machine. They DO NOT change the amount of work done. They DO change the size, distance, and direction of your force. The 3 main types of simple machines are levers, pulleys, and inclined planes. The wheel and axle, wedge, and screw are modifications of the three main types.
Inclined Plane
Lever
Second class- Like a wheel barrow, nutcrackers, and staplers. The fulcrum is to one side, the load is in the middle, and the effort is on the other side.
Third class- Some examples are shovels, baseball bats, and tweezers.The fulcrum is to one side, the effort is in the middle, and the load is on the other side (like your arm when you lift a weight)
Pulley
Wedge
Wheel & Axle
Simple machines are any of several devices with few or no moving parts that are used to modify motion and force in order to perform work. Machines are anything that makes work easier so even a ramp is considered a simple machine. They DO NOT change the amount of work done. They DO change the size, distance, and direction of your force. The 3 main types of simple machines are levers, pulleys, and inclined planes. The wheel and axle, wedge, and screw are modifications of the three main types.
Inclined Plane
- An inclined plane is a flat, sloped surface. It connects a lower level to a higher level.
- You use less force over a longer distance to raise a load to a higher level.
- Examples: Ramps (Boat ramps, wheelchair ramps) and ladders/stairs
Lever
- A lever is a simple machine made with a rigid bar free to pivot around a fixed point called a fulcrum.
- Levers may change the size, distance, or direction of the force.
- There are 3 types of levers:
Second class- Like a wheel barrow, nutcrackers, and staplers. The fulcrum is to one side, the load is in the middle, and the effort is on the other side.
Third class- Some examples are shovels, baseball bats, and tweezers.The fulcrum is to one side, the effort is in the middle, and the load is on the other side (like your arm when you lift a weight)
Pulley
- A pulley is a simple machine made with a rope, belt, or chain wrapped around a grooved wheel. They are used to raise, lower, and move loads.
- Pulley systems change the direction and/or decrease the input force so you can move heavier loads.
- Some examples of pulleys are door knobs, bicycle wheels, fans, cranes, raising a flag on a pole, a clothesline, and window blinds.
Wedge
- A wedge has slanting sides that meet at an edge- it splits materials apart.
- It is a modification of an inclined plane that moves. The inclined plane moves the load. It is made of two inclined planes put together to form a sharp edge.
- It changes force in one direction into a splitting force that acts at right angles to the blade.
- Some examples are an ax, knives, the blades of scissors, and zippers.
Wheel & Axle
- The wheel is locked to the central axle- when one turns, so does the other one.
- A short powerful force at the axle, will move the wheel's edge a long distance. A long motion at the edge of wheel, moves the axle with great force.
- It is a modification of the pulley and the parts must move together to be a simple machine.
- Some examples are screwdrivers, windmills, door knobs, bicycle wheels, and a fan.
- A screw has a "thread" or groove wrapped around a central cylinder.
- While turning, it converts a twisting force into a forward or backward force.
- Screws can hold things together or lift materials.
- Some examples of screws are classic screws, water bottle lids, light bulb necks, jar lids, and swivel chairs or stools.
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