Download PHYSICS 11: Notes Lesson 7:​ Work Energy Theorem

Date:____________________________
Name: ________________________________ PHYSICS 11: Notes Lesson 7:​
Work Energy Theorem Recall… ­
Work is a measure of _________________________________. Example 1​
: Drake lifts a 2kg ball straight up at a constant velocity. If the change in height of the ball is 2m, find the amount of work Drake does. In doing work, Drake has given the ball ________________. He gave the ball ______________________________________ energy. ­
An object can gain_________________________________ if an external force is applied to it, causing it to ______________________________. ­
The work required to accelerate an object is given by: ­
Energy is transferred to an object by doing __________________. Work Energy Theorem states that the work done on an object is equal to the _________________ in the object’s energy ­
This relationship can be expressed by: Example 2:​
How much work must Leo DiCaprio (75 kg) do to increase the speed of his 15kg bike from 8 m/s to 13 m/s? Machines ­
A machine is something that can do work and it usually makes work easier. ­
Machines ____________________________ the amount of work done but they do reduce the amount of ______________________ needed to do work. ­
Machines increase the ______________________ to reduce the ____________________________ required to do the same amount of work. Example 3: ​
A 75 kg box has to be lifted 1.5 m onto the back of a truck. Calculate the work done on the box if you lift it straight up. Now,​
find the effort force required to move the box a vertical distance of 1.5 m, but up a 5m ramp. ­
The ________________________ is the force you have to exert and the _____________ __________________ is the distance through which you had to exert it. ­
If the load force is greater than the effort force, we say that the machine has a __________________________________. ­
We can calculate the mechanical advantage: Example 4: ​
Calculate the mechanical advantage of the ramp in example 2.