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A boat is a form of transportation on the water. A boat like this has a speed of around 35mph and faster. There is a motor attached to the boat with a propeller to keep the boat moving, along with gasoline/diesel to fuel the motor. There are multiple forces acting on a boat, some of these forces include, acceleration, friction, and thrust. Simplified the acceleration is the boat moving through the water, the friction is between the water and the boat, and the thrust is the propeller moving through the water.

**Acceleration**  ** Definition of Acceleration: Increase in the rate of speed of something. **  To move at all, well to move fast (you are constantly moving even without the motor running because of the water current), a boat needs a motor and a propeller. The motor, just like a car, gets the boat moving through the water. But unlike a car, which has wheels to help the car moving fast, there are much needed propellers. The propellers rotate around pushing the water backwards so the boat can move forward, quickly. There is much resistance on the boat from the water, but with a high powered motor and propeller the boat pushes past the resistance to move quickly through the water. = =  **Friction**  **Definition of Friction:** ** The resistance that one surface or object encounters when moving over another. ** The friction on the boat is caused by the boat pushing on the water. Since the boat is rather heavy and moving fast, the friction is minimal, and the boat doesn't move that much in a straight line (it does bob up and down). There is little friction because the motor keeps the boat moving forward, and because the faster it goes the more the boat bounces up and down, and is not constantly touching the water. Say you turn the motor off, then boat is overwhelmed with friction from the boat touching the water and so the friction would slow down the boat until the boat catches the water current. Then the boat would be moving again, and the friction would decrease. But if you are flying by on a speed boat, and then cut the motor, your body would be thrown forward (there is not much friction with the air to hold you back) while the boats slows down.

**Motor Design and Function** A boat motor works like a car engine. There are a series of piston heads in cylinders that move up and down. The pistons are connected to a crank shaft, which turns as the pistons move up and down. The diesel or gasoline are what drive the pistons and causes them to move up and down. The more fuel that is pumped into the cylinders, the faster the pistons move, the faster the boat will go. A boat motor receives fuel through a pump just like a car. The pump is connected to a tank that holds gas. When the throttle is turned up, the tank pumps more fuel into the engine. In addition, the throttle valves open allowing more gasoline into the engine. The crank shaft is connected to a drive rod, and is connected to a propeller that causes it to spin, and causes the boat to accelerate. **Thrust** **Definition of Thrust:**
 * Drive System**
 * A force, especially one that produces motion, a propulsive force produced by the fluid pressure or the change of **
 * momentum of the fluid in a jet engine, rocket engine, etc., a similar force produced by a propeller **



A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid (the water) is accelerated behind the blade. A motorboat generates thrust, or reverse thrust from the propellers. This occurs when the propellers are turned to accelerate water backwards or forwards (which coincides with the reverse thrust.) The thrust pushes the boat in the opposite direction that the propeller turns the water flowing through the propeller.

**Cooling** A car motor and boat motor both have cooling systems, but they are different. A boat motor will use water to cool the engine. The water is flushed through the motor and then removed. **Physics Topic Categories:** Acceleration, Friction, Thrust (Force) **Video of a speed boat moving through the water:**  media type="file" key="Speed Boat-Physics.mp4" width="420" height="420" Video From: http://www.youtube.com/watch?v=Et6n64XhoyM **References:** “Acceleration.” //The Physics Classroom//. The Physics Classroom, 2011. Web. 13 Dec. 2011. . “Thrust.” //Wikipedia//. Wikipedia., 2011. Web. 13 Dec. 2011. http://en.wikipedia.org/wiki/Thrust Orton, Gregg. Boats... //Stupid Questions Answered//. Stupid Questions Answered, 2002. Web. 13 Dec. 2011. . Pictures: http://www.dreamstime.com/royalty-free-stock-image-boat-propeller-image10636606 http://www.premierboatworks.com/ http://stidge.com/image/6b2a53ed http://www.nauticexpo.com/prod/parsun-outboard-motor/boats-motors-4-stroke-out-board-motors-4-hp-27445-178640.html [|How Does a Boat Motor Work? | eHow.com] [|http://www.ehow.com/how-does_5008871_boat-motor-work.html#ixzz1h52efhW9]