Kinematics and Forces Test KEY + RUBRIC + INSTRUCTIONS
Facilitators,
You should have received a test with both a Multiple Choice (MC) section and a Free Response (FR)
section.
You have many options.
1) You may give the MC section as your test, and give the FR as ‘study-practice’ for the AP exam.
(Many sites are choosing this option, simply because of ease of grading, and rapid turn around
for student feedback). In this case the MC% is the full test %.
2) You may give both the MC and FR sections and grade them on-site using the rubric(s) below. I
would suggest this option only for facilitators with science background or at least a good grasp
of physics. This is the optimal option since it forces students to be accountable for all of it,
*and* results in a rapid turn around for student feedback. In this case the test % is the average
of MC% and FR%.
3) You may give both MC and FR sections to students, grade the MC on-site, and then send the FR
sections to the Academy for grading. We can provide this service for you if desired, but please
be aware that there could be a delay. If you do this, *please* keep copies of the tests… items
have been lost in the mail (either USPS or BSU campus mail) and it gets messy! Also please
make sure that if you take this option, students write legibly and dark enough to survive
copying. In this case the test % is the average of MC% and Test %, although you may have to
wait until you get the FR back from us before entering grades.
If you wish to give your students the true AP experience, the MC section should be taken in 17 minutes.
The FR section (if given) should have 21 minutes allotted.
Thus, if you choose to give both the MC and FR sections simultaneously, students should have no more
than (but *at least*) 38 minutes in which to take this test.
MC% = (total MC score / 10) * 100 = _______
FR % = (total combined score for both FR questions / 14)*100 = _____
Again, if you are giving only the MC questions, the test score is equal to the MC%. If you are giving both
the FR and MC questions, the test score is the average of the MC% and the FC% ((MC% + FR%)/2).
Projected AP grading scale =
A = 75% or higher
B = 55% or higher
C = 30% or higher
D = 20% or higher
Yes, this seems like a lenient scale, but AP questions are designed to be *challenging*.
RUBRIC
MC 1 point each
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
A
C
D
A
B
C
C
B
D
C
For those wishing to also grade the FR, the following rubric should be used
FR 1 (7 points total, broken down as follows)
(1 point) Any discussion regarding the Force dependence (right or wrong). Using a formula (or units)
that includes force (or “N”, “kg*m/s^2”) can count for this point.
(1 point) A discussion about the Force dependence, explaining qualitatively how the greater the force,
the greater the final velocity should be. If a formula or units were given, they must qualitatively explain
what the formula means (not just math or equations).
(1 point) Any discussion regarding the time dependence (right or wrong). Using a formula (or units) that
includes time, (or “s”) can count for this point
(1 point) A discussion about the time dependence, explaining qualitatively how the longer the force is
active, the greater the final velocity should be. If a formula or units were given, they must qualitatively
explain what the formula means (not just math or equations).
(1 point) Any discussion regarding the mass dependence (right or wrong). Using a formula (or units)
that includes mass (or “kg”) can count for this point.
(1 point) A discussion about the mass dependence, and a proper understanding that the greater the
mass of the object, the more resistant it is to acceleration (or forces) and the lesser the final velocity will
be.
(1 point) A discussion about how the object’s initial velocity is *not* part of the proposed formula, and
that it need be included if a true final velocity is to be found. This point can also be granted if the
student realizes that the proposed formula will solve for the *change* in velocity, not the final velocity.
FR 2 (7 points total)
A)
a
0s
5s
10s
15s
20s
25s
30s
t
(1 point) Having zero acceleration for 0-10s
(1 point) Having a constant, positive, acceleration for 10-20s
(1 point) Having a constant negative acceleration for 20-25s
(1 point) Having a constant positive acceleration for 25-30s (or beyond)
(1 point) Having the 20-25s acceleration dip below zero less than either the 10-20 or 20-25 rose above
zero, AND having the average of the 20-25s section rise higher above zero than the average of the 1020s section. (note that the “average” wording here is included to protect students who incorrectly do
not have ‘flat’ accelerations, but understood the 2nd acceleration would be greater)
B)
i)
X Greater than (1 point)
ii)
(1 point) A mention that the fuel is pushing down on the launch-pad, or a explanation of newton’s 3rd
law, or any understanding of equal and opposite forces from the thrust… AND any mention that any
force of the launch would be above and beyond the resting weight of the rocket, or any understanding
of newton’s 2nd law (F= ma), or that the forces will be added.
.