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NAME Motion Study Guide Work the following problems carefully

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NAME Motion Study Guide Work the following problems carefully Powered By Docstoc
					NAME: _________________________                                            2-D Motion Study Guide

Work the following problems carefully on separate paper. The work you produce will be
       your study guide. Show all your work, include units, and draw pictures.

Imagine that a man steps off of the edge of a tall building. Please answer the following questions
about the man:

   1.   What is his acceleration?
   2.   In what direction is the acceleration acting?
   3.   What is his initial velocity? In what direction?
   4.   How fast is he falling after 2.5 s?
   5.   How far has he fallen after 2.5 s?

Imagine that a car drives off of a cliff while traveling at 25 m/s (this is about 55 MPH). Please
answer the following questions about the car:

   6. What the car's acceleration?
   7. In what direction is the acceleration acting?
   8. What is the car's initial velocity in the vertical direction?
   9. What is the car's initial velocity in the horizontal direction?
   10. How fast is the car falling after 2.5 s?
   11. How far has the car fallen after 2.5 s?
   12. After 2.5 s how far has the car traveled away from the cliff (in the horizontal direction)?

Imagine that a projectile is shot out of a gun at an angle of 30° above the horizontal. The initial
velocity of the projectile is +400 m·s-1. Please answer the following questions about the projectile:

   13. What is the projectile's acceleration?
   14. In what direction is the acceleration acting?
   15. Assume that the vertical direction is the same as the Cartesian y-axis. What is the y-
       component of the projectile's initial velocity?
   16. Assume that the horizontal direction is the same as the Cartesian x-axis. What is the x-
       component of the projectile's initial velocity?
   17. What is the projectile's initial velocity in the vertical direction?
   18. What is the projectile's initial velocity in the horizontal direction
   19. What is the maximum altitude reached by the projectile?
   20. How many seconds does the projectile take to reach this altitude?
   21. How many seconds would it take for the projectile to return to the ground, assuming that it
       was shot from level ground?
   22. How far away from the gun would the projectile strike the Earth?
   23. Complete the table below for the projectile:

          Time     x-displacement y-displacement            x-velocity          y-velocity
           (s)           (m)            (m)                  (m·s-1)             (m·s-1)
            0

            8

           16

           24

           32

           40
NAME: _________________________                                            2-D Motion Study Guide

     Some Physics Problems for You to Enjoy™. These problems are similar to “word
                        problems” used on tests in the past.

   24. Jewel Liner goes out for a bike ride to a nearby town. A record of the trip is as follows: 30
       minutes at 30 km·h-1, 15 minutes at 40 km·h-1, 5 minutes at 0 km·h-1 for a break, and 20
       minutes at 25 km·h-1 .
       1. What is the distance Jewel traveled?
       2. What is the average velocity?
   25. Nerve impulses typically travel through the body at about 70 m·s-1. Imagine dropping a
       brick from one meter onto your big toe. Compare the time it takes for the brick to fall with
       the time it takes for the signal to get from your toe to your brain. Assume you are 1.75
       meters tall.
   26. Train A starts at 4 km South of a bridge and heads North at a constant speed of 20 m·s-1.
       Train B starts 6 km North of the bridge.
       1. What velocity must Train B have so that the two trains cross the bridge at the same
            time?
       2. If Train B goes at 15 m·s-1 , South, how far away from the bridge do they cross?
   27. Rumor has it, that one cool summer evening, a certain RHS faculty member contributed
       significantly to our understanding of gravitation and the effects of sudden changes in
       momentum on large fruit by dropping a watermelon off a local building1. Given that it took
       2.3 seconds before the ill-fated melon impacted the ground, how tall was the building?
   28. While sitting at a stop sign Mr. Chesnut glances up from his clock (4:48:10) when he notices
       that the woman of his dreams2 has just driven by (at a constant 20 m·s-1). Three seconds
       after she passes the light changes, and Mr. Chesnut accelerates to catch-up and pulls his car
       alongside hers before the next light. Just as his car reaches hers his clock reads 4:48:22.
       They live happily ever after.
       1. What was Mr. Chesnut's acceleration?
       2. How fast was Mr. Chesnut traveling when his car reached the car belonging to the
            amazing woman?
       3. How far did he travel to meet her?
   29. Mr. Bell fires his gun straight up in the air. Exactly 2.0 seconds later he is hit by the bullet
       falling back to earth. Fortunately he was wearing a Kevlar™ vest and is unharmed by this
       stunt. What was the muzzle velocity (v0) of the bullet?
   30. A model rocket is launched straight up in the air from rest and its engine delivers a constant
       acceleration3 of 8.2 m·s-2 for 5.0 s after which the fuel is used up. Ignore air resistance.
       1. Find the maximum altitude reached by the rocket.
       2. Find the total time the rocket is in flight.
       3. Calculate the rocket's impulse (change in momentum) over the first 5 seconds.
       4. How much work was done by the rocket's engine in the first 5 seconds. Do not forget to
            include work done against gravity AND work done accelerating the rocket?
       5. How high did the rocket fly before the engine quit thrusting?
   31. How much force would be required to accelerate a 25 g bullet from rest to 330 m·s-1 as it
       travels through a 70 cm gun barrel?




1 Don't try this anywhere, ever.
2 A billionaire, bikini-model, astrophysicist, who has an acerbic wit, a love of traditional blues
  music, and six toes on one foot.
3 This is the NET acceleration in the up direction, you do not need to adjust this acceleration for
  gravity.

				
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posted:3/27/2011
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