In this formative in-class Criterion C task, we connect the content from the last unit with some basics on Forces, using the Red Bull Stratos jump as a basis.

1. Intro Physics Name: _____________
Criterion C: Knowledge and Understanding (Formative) Introduction to Forces
Questions on this task fit the descriptors below.
Level Descriptors
0 The student does not reach a standard described by any of the descriptors below.
The student recalls some scientific ideas, concepts and/or processes.
1-2 The student applies scientific understanding to solve simple problems.
The student describes scientific ideas, concepts and/or processes.
3-4 The student applies scientific understanding to solve complex problems in familiar situations.
The student analyses scientific information by identifying parts, relationships or causes.
The student uses scientific ideas, concepts and/or processes correctly to construct scientific explanations.
The student applies scientific understanding to solve complex problems including those in unfamiliar situations.
5-6
The student analyses and evaluates scientific information and makes judgments supported by scientific
understanding.
1. State the names of three at-a-distance forces and three contact forces.
(L1-2)
At-a-distance Contact
2. Identify these situations from the free-body diagrams (FBD’s) (put the letter inside the box):
(L1-2)
a. Skateboard with rockets
b. Skateboard after the rockets
have run out
c. A helium balloon that is
losing its helium
d. Rose at the end of Titanic
e. MrT’s keys on the desk
3. Describe what is meant by the Normal force.
(L1-2)

2. Intro Physics Name: _____________
4. Describe what happens when there is an unbalancednet force acting on an object.
(L3-4)
Felix took a balloon a long way up into the sky, jumped out, fell for a bit in freefall, lost control a while,
recovered, went faster than the speed of sound and then deployed his parachute to land safely.
Some quick stats:
Jump height: 39,045m
Max speed: 1,342.8 km/h
Total freefall time: 260s
Freefall time to max speed: 40s(Time to Speed of Sound: 34s)
Total jump time 9min 9s
Felix’s mass with all the gear: 118kg
Sources: http://www.redbullstratos.com/blog/post/33739561019
5. Mass is a measure of the quantity of matter in an object (kg). Weight is a measure
of the force of that object being pulled to Earth. On Earth, objects have a weight of
10N per kg. Determine Felix’s weight with all the gear.
(L1-2)
___________ N
6. Calculate Felix’s average downward velocity in m/s over the whole jump.
(L3-4)
7. Calculate the average accelerationfrom standing on the platform to maximum speed (m/s/s):
(L3-4)
8. Suggest reasons why Felix’s average acceleration was slightly less than 9.8m/s/s.
(L3-4)

3. Intro Physics Name: _____________
9. Drawand labelfree body diagrams (FBD’s) for these situations.
Note: Air resistance is a function of velocity – so the faster an object moves, the greater the air resistance it
generates. A small, fast object can generate as much air resistance as a large, slow parachute.
This animation might help: http://www.mrwaynesclass.com/teacher/projectile/terminal/home.html
And this: http://www.physicsclassroom.com/mmedia/newtlaws/sd.cfm (L3-4)
a. The capsule on the ascent.
b. Felix before stepping off the platform
c. Felix as he accelerates in freefall Notes:
d. Felix at terminal velocity in freefall Gravity is constant
e. Felix and his parachute just after the parachute is opened FBDs are vector diagrams
f. Felix and the parachute at the new, slower, terminal velocity
10. Two of the FBD’s above should look exactly the same. Identify them and explain your choice.
(L5-6)

4. Intro Physics Name: _____________
11. Use information in the graph below (and your own reasoning) to suggest why Felix had to jump
from so high in the atmosphere in order to break the speed of sound.
(L5-6)
Adapted from: http://en.wikipedia.org/wiki/Atmosphere_of_Earth
12. Evaluate the claim that the Red Bull Stratos was a jump “from the edge of space.”
(L5-6)