PHY 2048
Midterm Exam 
DAY
Fall 2010
Use g = 9.80 m/s and G = 6.67 × 10
11
Nm
2
/kg
2
.
2
1. [15 points]
A 7.65 kg mass moves with a velocity given by the function
v(t) = (5t
3
– 7t
2
– 11) m/s.
What is the force acting on this mass?
Give your answer as a function
of time with numerical values specified
with the correct number of significant figures.
2. [15 points]
The unknown
mass M is hanging from a rope
attached to a wall at the known angle
2
as shown
and pulled to the left by a known force F.
Draw
a clear freebody diagram and solve for the tension
T in the rope in terms of the known
parameters.
3. [20 points]
A 1.76 kg mass
m
starts at rest at point
A
with the 9738 N/m spring
compressed by 0.086 m.
It strikes and sticks to the 2.97 kg mass
M
, which
then slide together across a rough surface that provides a friction force
of 5.85 N.
How far do they slide before stopping?
Show your wellorganized calculation below.
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View Full Document4. [15 points]
A 0.356 kg projectile is launched at 43.5 m/s at a 57.8° angle above horizontal.
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 Fall '08
 Laposky,E
 Physics, Force, Friction, Mass, Velocity, kg mass, race car

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