Bell Work 3/16/15 Scissors are an example of which simple machine? A inclined plane B wedge C lever and a wedge D wedge and a screw Explain your answer by describing the function of the simple machine(s) you choose.
Agenda 1. Bell Work 2. Objectives 3. Simple Machine Review 4. Calculations Review/ Practice 5. Quiz
Objectives Can I apply proper equations to solve problems pertaining to distance, speed, time, and velocity?
Work Review 1. What is work? Work is when force is exerted and an object moves in the direction of the force. 2. What is mechanical advantage? Mechanical advantage is the number of times a machine multiplies force. 3. What is a machine? A machine is a device that makes work easier by changing the size or direction of force. 4. How is work calculated? Work is calculated by multiplying force times distance.
Simple Machine Review What is a practical application of each of the following?: Lever Inclined plane Screw Wheel and axle Wedge Pulley
Simple Machine Review 1. A lever rotates on a ______________________ A rotator B axel C fulcrum D pin 2. What is one way in which simple machines make work easier? A improving the quality of axles used in cars B eliminating the need for workers to apply any force when completing tasks C decreasing the amount of force necessary to complete a task D creating the need for more workers
Calculations Review 1. What is motion? Motion is the change in the position of an object as time changes. 2. What is the difference between speed and velocity? Velocity has direction, and speed does not. 3. What are the two factors that determine speed? The two factors that determine speed are distance and time. 4. What is the equation for speed? Speed= distance/ time
Calculations Practice 1. How much force was applied to a box that required 45 joules of work to push it up a 3-meter-long ramp? 2. A construction worker used an inclined plane to move a box of bricks. He applied a force of 25 newtons and moved the box 4 meters. How much work was done? 3. If the work done is 280 J, and the force used to do the work is applied over a distance of 7 m, what is the value of the force?
Calculations Practice 1. Sound travels at a speed of about 340 meters per second in air. If a person hears a police siren 170 meters away, how long did it take the sound to travel from the police siren to the person’s ear? 2. A boat leaves the dock and travels west. The boat travels for three hours. At the end of three hours, the boat has traveled 36 km. What is the average velocity of the boat? 3. A ship is traveling at 32 km/h between ports that are 480 km apart. How long will the ship take to make the trip?