LUG and test reviewMonday, October 6, 2014

Monday, 10/6 Unit 3: Work and Forces

Pick up warm-up sheet from Physics bin Write the question in the box for today and answer it. If you need

more room write it on the back. You have 3 minutes to complete. I will collect the weekly warm up sheets at the end of the week.

Read the ‘I can’ statements on the side board. Review dates below

Upcoming dates Wednesday, 10/8 – quiz Wednesday, 10/8 – Mrs. Cheyne will not be at school Friday, 10/10 – Unit 3 test Friday, 10/24 – last day to turn in 2SW extra credit Friday, 10/31 – end of 2SW

Warm-up1. A rock with a mass of 5 kg is attached to a string and a child is applying an upward force to the string. Use the diagram below determine the Net Force.

Fg = 49 N

Ft = 15 N

2. A rock with a mass of 5 kg is attached to a string and a child is applying an upward force to the string. The rock is accelerating 6.8 m/s2 downward. Calculate the net force and determine the FT on the string.

Fg = 49 N

Ft = _____

Law of Universal Gravitation

Video http://dsc.discovery.com/videos/assignment-di

scovery-shorts-newtons-explanation-of-gravity.html

Take LUG notes

Review Equation What does the G in the equation mean?

Will it ever change? Describe the relationship between mass

and distance between the objects. What variable has greatest role in

evaluating the force of gravity between objects? Support your answer

Practice Problem 1Tom has a mass of 70.0-kg and Sally has a mass of 50.0-kg. Tom and Sally are standing 20.0m apart on the dance floor. Sally looks up and sees Tom. She feels an attraction. If the attraction is gravitational, find its size. Assume that both Tom and Sally can be replaced by spherical masses.

Practice Problem 2

What is the gravitational attraction between two spheres (msphere = 1.67 X 10-27 kg) at a distance of 5.0 X 10-15 m?

7.44 x10-36 N

Practice

Reveiw