Final Exam review
Physics 201
Short Answer (4 pts each)
1-4. Label the SI units of the following quanities. If the unit is composite, list the basic components as well:
Quantity / SI unit name / Basic components (m, rad, kg, and s)Angular velocity
Energy or Work
Power
Momentum
5. What is the angle between centripetal acceleration and tangential velocity?
6. If a particle located at the right margin of this page is tied to the number 6 (left margin) and is moving into the page, what is the direction of angular momentum?
7. Are collision forces typically greater in an elastic or inelastic collision? How do you know?
8. What quantity can be found by taking the derivative of the potential energy function with respect to distance?
9. During an elastic collision with target with v0=0, what combination of masses results in a final velocity equivalent to the initial velocity of the striking object?
10. What is the value of the angular acceleration of an object with constant w?
11. What is the direction of the total system momentum for 3 identical sparrows flying at the same speed, where one flies North, one flies West and one flies Northwest?
12. Circle the following vectors and underline the scalars:
q a t p w F U x W K.E. P m
angle acceleration time momentum ang. velocity force pot. energy position work kin. energy power mass
13. Which 3 of the following quantities are in the same direction for single object?
Dx Dv Dp Dw DU DE Favg
14. What direction is the gravitational torque on your heart about point A?
15. What causes a spinning top to precess (wobble about the vertical axis)?
16. If all of the following objects have the same mass, which has the greatest total kinetic energy when rolling at 50 mph?
Solid Ball Disk Hoop Hollow ball
Problems, 12 pts. each
1)
On the moon, a feather is dropped from a height of 1.5 meters. What is its weight compared to that on earth? What is its speed when it strikes the surface? The moon experiences an acceleration of gravity of a=1.6 m/s^2 and has no atmosphere.
2)
Taking exit 4 off of I-95 on a rainy night, we are rounding the exit ramp at 40 mph. The curve has a radius of 55 meters and the our tires claim to have a coefficient of static friction of .60 on wet pavement. You may assume the curve is not banked. Will we skid off into the berm, or make it home safely?
3)
I am trying to push my car out of a ditch. The ditch has a slope of 9 degrees. The tires stuck in the mud have ms=.35. My car has a mass of 1100 kg. I am strong enough to generate about 900 N of pushing force. How many friends do I need to help me get the car out (assuming they are equally as strong)?
4)
A cross-bow arrow is shot into a block of wood at the base of a ballistic pendulum. The pendulum weighs 780 g, the arrow is 11 g, and the shot results in a swing through 42 degrees. The center of mass of the pendulum is 53 cm from the pivot point. What was arrow’s initial velocity?
5)
My eight-iron has a mass of 165 g and strikes a teed-up golf ball with a mass of 49.6 g in a completely elastic collision. The club has a loft of 36 degrees (this is also the ball’s launch angle). What swing speed do I need for a 146 yard par 3? You can ignore air resistance. 1 yard = .914 m.
6)
A 400 gram block is attached to the end of a spring with k=78 N/m and rests on a table, with mk=.43. You stretch the spring 30 cm from equilibrium and let go. The spring retracts and accelerates toward equilibrium, passes equilibrium and begins to compress. What is the velocity of the block as it moves through the equilibrium position the first time and what is the position of the block at the first turning point?
7)
“You gotta serve somebody”, the first track of Bob Dylan’s “Slow Train Coming” is playing on my 33.33 rpm record player and runs for 4:12 (four minutes, 12 sec). The record plays as a small stylus slides though a continuous v-shaped groove that spirals around the record. The vinyl record has a diameter of 12 in. and it has 265 grooves per radial inch. 1 inch = 2.54 cm.
a) If the record begins playing at the outside edge, what radial thickness has the first track used?
b) Find the angular velocity and the tangential velocity at the beginning and end of this song.
8. A 3.5 kg bowling ball rolls smoothly down this ramp and up a hump. Does it fly off the top of the hump? If not, what is the normal force at this point? The rotational inertia of a solid ball is: I=(2/5)MR2