Problems - Shawn Cornally

Physics: Total Reassessment
We’ve spent a lot of time working in groups, creating
experiments, and working through tough problems
and situations. Now it’s time to find out how much
of that each of you has in your noggin.
1. Work each prompt by yourself or with your
team. If you’d like your score changed, show me
your work individually.
2. Feel free to ask for my help.
3. State which standards you think the problem
addresses.
Thursday, January 3, 13
Which standards?
Pulleys are Pull-y
A frictionless pulley is suspending two
masses as shown. Gravity is down the page.
Pulley
What is the acceleration of the 10 kg mass?
[It’d be nice if it were -5 m/s/s, but that is never
seen in real life]
5kg
10kg
Thursday, January 3, 13
Which standards?
Save the Puppies!
v0 = 1.5 m/s
A box of puppies is kicked accidentally slid
down a boat ramp. The sharks have learned
to wait at the bottom of the ramp to get an
easy meal.
The boat ramp is 15 m long, and puppies
started with 1.5 m/s. What must the
coefficient of friction be for the puppies to
stop just short of certain doom?
15º
Thursday, January 3, 13
Which standards?
Nuclear v. Petrol
Gasoline has 140 million Joules in each
gallon. How much gas do you have to use to
get a 600 kg car up a 12 meter-high onramp and up to 70 mph from a stop sign at
the bottom of the ramp?
What are the frictional forces on the car if
its 10-gallon tank runs out of gas 270 miles
later?
How much farther could the car go if it was
powered by a fission reactor with just 0.01
gallons of nuclear fuel? Fissionable Uranium
has 6 billion million Joules per gallon.
Thursday, January 3, 13
Which standards?
Huge in Finland
35 m
30º
A ski jumper starts at the top of a 145 m
mountain. The jumper takes a kicker ramp
angled 30 degrees. How far to the right of
the kicker ramp does he end up?
110 m
?
Thursday, January 3, 13
Which standards?
Winter Driving
When a car’s tires spin out on ice, why is it
better to lay off the gas than to push the
pedal harder?
How are the following affected by winter
driving conditions?
1. Acceleration
2. Top Speed
3. Turning
Does our model of friction predict that
SUV’s will do better or worse than normal
cars in the winter? Why?
Thursday, January 3, 13
Which standards?
Rock, Paper, Scissors, Lizard, Spock
In a game of RPSLS, why would you have to
put the lizard’s head closer to the scissor
joint than the paper?
Thursday, January 3, 13
Which standards?
Rubbin’s Racin’
Who wins a 1.5 km drag race if each car starts at the
same time at 0 m/s?
Draw a d v. t graph and v v. t graph for all three cars.
Car
Thursday, January 3, 13
Top Speed (m/s) Acceleration (m/s/s)
Alpha
70
4
Beta
90
3
Gamma
55
9
Which standards?
Thanks, Biebs
According to recent research, the existence of
Justin Bieber is causing global climate change
through the fossil fuel used to manufacture all
of his useless merchandise. Which model most
accurately models the data?
Temperature T [F] vs. Years of Beiber Existence t
67
66
65
64
Model 1: T = 0.33 t
63
Model 2: T = 0.4 t + 50
62
Model 3: T = -0.4 t + 60
61
Model 3: T = -0.4 t^2 + 60 t + 59
Thursday, January 3, 13
60
59
1990
1996
2002
2008
2014
Which standards?
Chicken
In a game of chicken, where both
players lose, a 10 Mg Mack Truck
and a 2 kg cat (riding an invisible
Segway) collide. How fast were
they moving, if the collision results
in both parties coming to a
complete stop?
Thursday, January 3, 13
Which standards?
A Classic
T1
T2
52º
34 kg
Thursday, January 3, 13
33º
What is the tension T1?
Gravity is down the page.
Which standards?
Space, the Final Frontier
At what distance from Earth is the force of
its gravity half of what it is on the surface?
What would your velocity be in this orbit?
What should the solar system look like
(from above) on the day NASA launches
the mission to Mars?
What is the acceleration due to gravity
when riding in an airplane at 40k feet.
What will the trajectory of the craft look
like in space?
What are the densities of Earth and Mars?
How long will it take?
Orbital Radius [km]
Body Radius [km]
Mass [kg]
Earth
150 million
6,371
5.97E+24
Mars
225 million
3,396
6.41E+23
Thursday, January 3, 13