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Science
Chapter 12 Simple Machines
| Question | Answer |
|---|---|
| What is the variable that is varied or manipulated? | Independent Variable |
| What is the variable that is the response that is measured? | Dependent Variable |
| What is work? | Work is defined as a force acting through a distance For example lifting something up or pushing something to make it move |
| What is the formula for work? | Work = Force x Distance = W = Fd |
| What is a joule (J) | A joule (J) is an amount of work or energy that is equivalent to applying a 1 Newton force to an object for a distance of 1 meter. |
| What is Power? | Power is the rate at which work is done Power = Work/Time |
| What is a machine? | A machine is a device that makes work easier. |
| What 3 ways can machines make work easier? | 1. Changing distance 2. Changing force 3. Changing direction |
| True or False Machines can make work easier by making less work | False |
| True or False The work that is put into a machine is theoretically equal to the output work (WI = WO) | True |
| A comparison of input work to output work is called? | Efficiency |
| No machine is 100% efficient due to ... | friction and inefficiencies |
| Machines with the smallest amount of friction , | tend to be the most efficient. |
| True or False The greater the mechanical advantage, the less force is required to do the work. | True |
| The formula for Mechanical Advantage is | Output Force / Input Force = MA = FO/FI |
| Ideal machines theoretically have an efficiency of | 100% |
| An inclined plane | is a flat, sloped surface like a ramp. |
| What are the 6 simple machines? | Inclined plane, wedge, screw, lever, pulley, and wheel and axle |
| True or False The longer the inclined plane is, the less force is needed to raise the object because of the decreased slope | True |
| A wedge is | a movable inclined plane |
| True or False A screw is an inclined plane wrapped around a central bar or cylinder to form a spiral. | True Example is a threaded jar lid |
| A lever is a rigid bar that is free to pivot about a fixed point called a fulcrum. | a rigid bar that is free to pivot about a fixed point called a fulcrum (for example, a see-saw) |
| There are three classes of levers (think FRE)? | A first class lever has a fulcrum in the middle. A second class lever has the resistance in the middle. A third class lever has the effort in the middle. |
| A pulley is | a rope, belt, chain, cable, etc. wrapped around a wheel |
| The ideal mechanical advantage of a moveable pulley system is equal to | the number of lifting lines (the number of sections of line that support the object). |
| A wheel and axle is a simple machine made from | two circular or cylindrical objects of different sizes that are fastened together and rotate about a common axis (example is the gears on a bicycle) |
| The human body hosts a number of simple machines - name two | 1. levers made from bone and muscle 2. wedges in the form of teeth. |
| A combination of two or more simple machines is called | A compound machine |
| The mechanical advantage of a machine that changes on the direction of a force is | 1 |
| The stationary point that a lever pivots around is called | a fulcrum For example, a seesaw is a lever that has a fulcrum in the middle or a knee on your leg |
| The faster a set amount of work is done | the higher the power |
| Another term that can be used for output force is | resistance force |
| The ideal mechanical advantage for an incline plane is | the length of the plane divided by the height of the plane |
| True or False Positive work is done on an object when the object moves in the same direction in which the force (or component of the force) is exerted. | True |
| The ideal mechanical advantage would equal the actual mechanical advantage if there were no losses due to | Friction |
| What are the important parts of a pulley | Wheel, Axle, Rope (or chain) |
| What is the MA (mechanical advantage) of a lever? | Ideal = Di/Do effort Fo/Fi EAL/ERL (effort arm length/effort resistance length |
Created by:
mredman