Callegard
Unit 2 FRQ Possible Questions
A group of students has a collection of parachutes of different radii. They are curious about how the terminal
speed depends on the radius of the parachute and find the following equation on the Internet.
N
m/s
Fair Cru
where Fair is the force exerted by air, r is the parachute's radius, v is the parachute's speed, and C is a constant
that has appropriate units.
(b) Determine the units for C.
N-
-C(m)(m/s) ²
N = c(m) (m²/5²)
N=C (m³/s²)
C=kg/m²
• kg/m².
The units for Care
(c)
Test Booklet
Based on the above equation for Fair, derive an equation for the system's constant terminal speed vt in terms
of r, C, physical constants, and other relevant quantities that can be measured with equipment usually found in
a school physics laboratory, as appropriate. Assume the mass of the parachute is negligible and that the only
nonnegligible forces acting on a block-parachute system are the block's weight mag and the force of air
resistance Fair
V =
Fair
Cr
ii. Indicate below what quantities could be measured and then graphed to determine whether the equation
derived in part (c)(i) correctly relates the parachute's radius and the terminal speed of the block-parachute
system.
Vertical axis:
Horizontal axis:
iii. On the axes below, sketch a graph showing the relationship between the two quantities indicated in part
(c)(ii) and based on the equation derived in part (c)(i).
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