Some review problems
Physics I, final exam
These problems combine concepts from multiple chapters.
One of these specific problems
will be on the final.
Note that the given variables are given in red, and the symbolic answers should
have only these and constants in the equations.
From the final exam front page!
• Provide clearly readable answers to the questions in the space
provided or on additional sheets.
• In all cases, clearly box your final answer
• In all cases, your symbolic answers must be in terms of the given
info.
• Show all work to obtain full credit.
• Attach additional pages if necessary to show additional work.
• There are 152 points total.
• A calculator is necessary.
• An equation sheet is provided on the last two pages.
• For gravity you should use g = 9.8 m/s2
• You must report proper units and correct significant figures when
possible.
To use in class….
i. what friction coefficient needed to keep a kid
on a merry go round.
ii. Write the x,v,a plots for my motion
iii. 2d collision
iv. Loggerpro data of pendulum oscillation
i.
Jan-2 file: energy, vmax, A, q, T, f
v. Block mass M accelerates up a slope q with
pull of rope by pulley and mass m. What is
a?
1.
• A car of mass M coasts down a ramp of height
h without friction and then brakes to a stop on
a flat road in distance L.
a. What is the velocity at the bottom of the ramp?
b. What is the acceleration during braking?
c. How much heat energy is generated by the
brakes?
d. What power is generated by the brakes.
e. What is the coefficient of friction during the
stop.
2.
• A man mass M jumps from a building height H to
a trampoline that goes down a distance x. It then
delivers that spring energy to launch the man at
450 across the street.
a.
b.
c.
d.
e.
What is the spring constant?
How far away from the tramp does the man land?
Does it hurt?
How high does he bounce in projectile flight?
How much heat does he generate when he lands?
3.
• A helicopter rotor of radius r is spinning at w0.
A small piece of mass M breaks off the tip of a
rotor and skids a distance L to a stop on the
runway. (neglect the vertical drop it had)
a. Calculate the coefficient of friction between the
rotor piece and the concrete.
b. How fast was the piece going after it broke off
but before it started skidding?
c. (note that the second part is needed before the
first part can be answered.)
4.
• I have a metal hoop of radius R and mass M
that I roll on the ground at speed V.
a. How far L up a slope of angle q will the hoop roll
before it stops?
b. If I double the mass, how far will it roll up the
slope?
c. If I double the speed, how far?
d. *If I paint it red, how far?
5.
• This is WonderWoman pushing with horizontal force F a car
of mass M for time T.
a. How fast is the car going if it started at rest?
• After WW stops pushing, Diabolical Man then drops a
boulder of mass 2M onto the car.
b. What is its new speed?
• Then the car enters a flat curve of radius R.
c. What friction coefficient is necessary to keep the car from sliding
on the curve?
• The car then hits Stupendous Student who stops the car in
time T (yes, the same time T as WW pushed the car).
d. *What average force did the car put on Stupendous Student?
6.
Support 1
Support 2
• A car of mass M drives out on this beam of
mass m and length L at speed V. The supports
are ¾ L apart and height h.
– Derive a relation for mass m necessary so the
beam doesn’t tip as the car reaches the end.
– How far from the end of the beam will the car fly
horizontally before it hits the ground?
– How much energy will the car have when it hits
the ground?
7.
• *A cubic block of side S and mass M uniform
density is on a adjustable ramp with
coefficient of friction ms. I lift the ramp and
the box either tips over or slides. What is the
critical ms so that the block slides just before it
tips? Hint, find angle q of tipping the box and
the m needed to keep it from slipping at this
angle.
8.
• I have a piano of mass m on a ramp with
coefficients of friction ms and mk. I raise the
ramp until the piano slips free and then it
slides down distance L.
a. What is q where it starts sliding?
b. How fast is the piano going at the bottom?
• It then hits a man of mass M at the bottom.
c. What is the velocity of the piano after the man is
stuck to the front of the moving piano?
9.
• Clay Man, mass M and speed Vc, and his arch
rival, Putty Woman, mass m at speed Vp, are
racing from different places to grab the Lucky
Locket of Lichtenstein. They collide at an
angle of 300 (angle difference from head-on)
and stick together.
a. What is their final velocity?
b. How much energy is lost in this collision?
10.
• A Paper towel roll of mass M is dragged on the
counter to give this data shown.
– What is ms and mk?
11. Demo PP cannon
• If the pingpong cannon length L is shot, and
the force on the ball mass m is constant F=P A,
then
a. what is predicted acceleration in tube?
b. What is predicted v at end of gun of length L?
c. What is predicted energy at the end?
• The ball hits the paper towel roll of mass M
which slides distance x with m given
d. What work was done on the roll?
12. Mass spring collision
• A block M is attached with spring k to a wall, on
frictionless table. A ball of clay mass m and
horizontal velocity v hits the block and sticks and
it all starts to oscillate. Derive
a.
b.
c.
d.
e.
Period
Amplitude
max velocity
energy
*If instead, there is friction m, then what is
remaining energy after 1 full cycle?
13. Pendulum
• A bowling ball mass 4.0 kg is hung from a rope
length 2.0m. I hold the rope parallel to the
ground and let go. At the bottom, the ball hits a
large block of clay of mass 30.kg that sticks. Find:
a.
b.
c.
d.
e.
f.
velocity of ball before collision
Velocity of ball after collision
tension in rope before I let go
tension in rope before the collision
Frequency of swing after collision
*Height of swing after collision
14. Demo 2
I roll the bowling ball mass M down the hall, length
L in time T (you can assume it doesn’t slow down
during this roll). To get the ball started, I pushed it
for distance D and then let go. At the end, the ball
hits the wall and stops.
a.
b.
c.
d.
e.
f.
What is acceleration of my push?
What is force of my push?
What is the energy of my push?
What is average power of my push?
What impulse is delivered from the wall to the ball
at the end?
*How much energy is delivered to the wall at the
end?
15. Throw the ball
• I throw the timer ball and it lands in 1.5 s and
has max height of 0.75m.
a. What is distance R?
b. What is initial velocity?
c. What energy does it have in flight?
*Galileo’s paradox
• An object falling frictionlessly along any chord
from the top of a circle will hit the circle edge
at the same time.
• Challenge problem:
– Prove this.
The cycle of each chapter
exam
introduce
new topic
finally get
it!!
review for exam
demos
define new
terms
introduce new
laws
panic!!!!
do a lab
apply to new
problems
a list of classics