Friday (15 Oct):

Key Concept's) Today: Review for test

Mon 18 Oct: Test Newton's Laws

& L #  7, 8, 10, 11, 14

Journal: 

For years, space travel was believed to be impossible because there was nothing which rockets could push off of in space in order to provide the propulsion necessary to accelerate. This inability of a rocket to provide propulsion is because ...

a. ... space is void of air so the rockets have nothing to push off of.

b. ... gravity is absent in space.

c. ... space is void of air and so there is no air resistance in space.

d. ... nonsense! Rockets do accelerate in space and have been able to do so for a long time.

1. a. Draw a Free Body Diagram of 50kg object that is being pulled to the right with a force of 200N

and has m of 1.5

b. Find acceleration

                                                            200N

                          50kg

2. a. Draw a Free Body Diagram of 50kg object that is being pulled up an frictionless incline plane at a constant speed.

b. Draw a Free Body Diagram of 50kg object that is being pulled up an incline plane with friction at a constant speed.

L #9: 1- 8,  11-16    Due Wed 20 Oct (Torque)

L #12: 1- 14,  16, 17    Due Fri 22 Oct (Work & Power)

L #13: 1- 13,  18, 19    Due Mon 25 Oct (Instantaneous Vel & Acc)

3. What net force is needed to accelerate a 20 kg object with acceleration of 4g (40m/s²)?

4. If the weight of an object is 100N and the acceleration is 6.0 m/s² in the Vertical direction, what is the object’s apparent weight (normal force on the object)?

5. Name the ways that an object can be accelerated.

6. An object moving in space went from a velocity of 50.0 km/hr to a velocity of 10.0 km/hr in 2.0 hrs. Find the average acceleration during the 2.0hrs.

7. The graph above shows the velocity versus time for an object moving in a straight line.  What is its displacement after 4 seconds?

6. Find the coefficient of Kinetic friction (m_k) between a 5 kg box that is moving across the floor with an acceleration of  6.0 m/s² (to the right). The horizontal force applied is 50N.

F_net = ma  --> (5kg)(6m/s²)  = 30N

F_net = T - F_K = 30N

           50N - F_K = 30N  

         --> F_K = 20N

               F_K = m_k(F_N) = m_k(mg)

               20N = m_k(50N)

             m_k   =  (20N/50N) =  .4

7. What does the slope of a line represent on:

a) Position vs time (Pt)

b) Velocity vs time (Vt) graphs?

c) Area under the curve on (Vt) graphs?

Video:

http://videos.howstuffworks.com/hsw/17164-elements-of-physics-newtons-three-laws-of-motion-video.htm

http://videos.howstuffworks.com/hsw/8483-exploring-the-laws-of-motion-newtons-third-law-video.htm