Physics 11 Mr. Jean March 30th, 2012

The plan: Video clip of the day Unbalanced forces Forces & Acceleration Inclined Plane problems Inclined Planes & 2d forces

Situation:

Questions: Using the image of Wile E. Coyote, determine the following values. 1) What is the coefficient of friction? 2) What is the mass of the rocket & Wile E.? 3) What is the acceleration of Wile E.?

HW for Monday: Read pages 188 – 194 Chapter #5 from McGraw-Hill Ryerson.

Example: Old TV’s and computer monitors produce pictures by firing electrons into a screen. The viewers sees the electron as a light change and this creates the resulting image.

TV Example: An electron with mass 9 TV Example: An electron with mass 9.1 x 10-31kg is accelerated from rest. Find the velocity of the electron if it experiences 5.8x10-15 N over a distance of 0.0035m.

Draw the “Force Diagram”:

Acceleration?

Lessons to follow:

Forces in two-dimensions: A 45kg crate is being pulled eastwards horizontally across the floor. The coefficient of friction is 0.2. You pull the crate with a force of 115 N at an angle of 15 degrees. What is the acceleration?

Draw the “Force Diagram”:

Write down the known variables:

Begin to solve the problem: Find normal force: NOTE: We must account for upwards pull by rope. (Fvertical will reduce Fn’s load) Fn =

Find Force of Friction: Ff = is opposing the horizontal acceleration Once we find Ff we can then compare the Fnet to determine the horizontal motion.

Problems to work on: P. 171 Question #11 & 12 Solutions in 20 minutes

Solutions: