then the work done is, if the force and the displacement are in opposite directions, then the work done is.

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Silas Holmes
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2 1. What is the formula for work? W= x 2. What are the 8 forms of energy? 3. Write the formula for the following: Kinetic Energy Potential Energy 4. If the force and the displacement are in the same direction, then the work done is, if the force and the displacement are in opposite directions, then the work done is. 5. What is the formula for efficiency? 6. A fork lift moves 50 meters carrying a 2000N box across the warehouse floor. How much work is done by the fork lift? 7. How long was the video we watched yesterday? 8. How many exits are there on a school bus? 9. What was the bus driver s number one rule? 10. What is the formula for power?

3 Both liquids and gases are fluids They both flow, have no definite shape of their own, and conform to the shape of their container. Force = push or pull; measured in Newtons or pounds. Force applied over a surface is pressure Measured in N/m2 or pounds per square inch (psi) P=F/A

4 As liquid flows into the large container at the bottom of this illustration, pressure pushes the liquid equally up into the tubes above the container. The liquid rises to the same level in all of the tubes, regardless of the shape or angle of the tube.

5 There are two types of fluid systems Open Has the fluid flow through it one time Example: fire truck water system Closed Retains and recirculates a working fluid Example: hydraulic jack

6 All fluid systems have two things in common 1) Contains a fluid (liquid or gas) that moves through a system of connecting pipes and devices. 2) A pressure difference in the system creates a net force. - This is what causes the fluids to move or perform some special function like pushing a piston or opening and closing a valve - makes sense, because pressure is the prime mover in fluid systems.

The hydraulic lift works on the principle that the effort required to move something is the product of the force and the distance the object is moved.

7 The hydraulic lift works on the principle that the effort required to move something is the product of the force and the distance the object is moved. By using an incompressible fluid to transmit the force, the hydraulic lift allows a small force applied over a large distance to have the same effect as a large force applied over a small distance. In this way, a small hand pump may be used to lift an automobile. In order to fill the large cylinder under the car with fluid, however, the small pump must be operated many, many times.

8 Closed Fluid System In a closed fluid system, the pressure is constant The work done by the system W, is equal to the pressure multiplied by the change in volume of the fluid W= P x V

9 If the fluid volume increases, V is positive, and W is positive. Positive work means the fluid does work. Example: when a gas expands in a cylinder, lifting a load.

10 If the fluid volume decreases, V is negative, and W is negative. A negative value for work means that work is done on the fluid. Example: a weight or force applied to a piston compresses the gas in a cylinder. This applied force does work on the gas.

11 In an open system volume is constant and pressure changes W= - P x V If pressure increases, then P is positive and W is negative. As before, this would mean that work is done on the fluid Pump If pressure decreases, then P is negative and work is positive, this means that the fluid does work. Hydroelectric dam water flows from high pressure to low pressure and turns a turbine, doing work.

12 An industrial robot moves objects with hydraulic cylinders. Each cylinder contains a piston and a working fluid (oil). The oil is forced into the cylinder under high pressure on one side of the piston. The oil pushes against the piston. This causes the piston to move. The other end of the piston is connected to a load. As the piston moves, it moves the load. The fluid is injected into the cylinder at a constant pressure of 89 kpa. The cross sectional area of the cylinder is 12 cm^2. Find the work done by the hydraulic fluid while moving the piston and load 10 cm.

13 A community s water supply is stored in an elevated tank to maintain water pressure. The tank is filled by water pumped from a reservoir 150 feet below the inlet to the tank. The tank has a volume of 5000 ft^3. If the tank is empty, what minimum work must be done by the pump to fill it?

In the liquid phase, molecules can flow freely from position. another. A liquid takes the shape of its container. 19.

In the liquid phase, molecules can flow freely from position to position by sliding over one another. A liquid takes the shape of its container. In the liquid phase, molecules can flow freely from position