Presentation on theme: "Bellwork A box of San Francisco 49ers jerseys is pushed with 80 Newtons of force for 5 meters up a ramp into a truck with a height of 1 meter to be taken."— Presentation transcript:
Bellwork A box of San Francisco 49ers jerseys is pushed with 80 Newtons of force for 5 meters up a ramp into a truck with a height of 1 meter to be taken to the thrift store. How much work did the person do on the box?
Mechanical Advantage & Efficiency How do machines do work for us? We can compare the amount of force put into a machine with the amount of force it produces This ratio is a machine’s mechanical advantage Mechanical advantage = (output force) (input force)
Can openers are simple machines that multiply the amount of force we input into opening a can If you use 5 N of force to open a can, and the opener exerts 15 N of force, what is the opener’s mechanical advantage? Output Force Input Force 15N/3N = 3 Your force is tripled!
A lever is used to lift a heavy rock. The mechanical advantage of the lever is 4 and the lever applies a force of 800 N to the rock. What is the force applied to the lever?
Consider this pulley: If only the direction of force is changed, what is the mechanical advantage? 1/1 = 1 No force is multiplied, but the work is easier. Why?
In elevators… Here is where the people go Counterweight
When using a pulley with a mechanical advantage of 1.5, a worker applies 250 N to the pulley. The pulley is used to lift a heavy crate. How much force does the pulley apply to the crate?
A 100 N force is applied to a machine to lift an object with a mass of 45 kg. What is the machine’s mechanical advantage?