Name:___________________

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Equations
Name___________________ In-class activity
acceleration, free fall, etc February 6, 2009.
Physics 50 Mechanics
Remember that acceleration due to Earths gravity
is -9.8 m/s2,where the - sign is due to having
up be the positive direction.
1. The figure below shows a graph of position vs.
time, of squirrel running along a power cable.
Warning Acceleration is not constant in this
problem.
On the axes below, graph v vs. t and a vs t. .
The vertical axes of your plots do not have to be
exact, but be careful of where is it is positive
or negative, what its slope is, etc.
a (m/s2)
v (m/s)
t(s)
t(s)
2
2. A remote-controlled car has a position vs time
given by
a) Find the position and the acceleration when
the cars velocity is zero.
b) Sketch the position vs. time, velocity vs.
time and acceleration vs time on the axes below,
for the time period between 0 and 2 seconds.
x(m)
v(m/s)
a(m/s2)
t(s)
t(s)
t(s)
3

• 3. A hot air balloonist is rising verticaly at a
  speed of 5.00 m/s as shown. When the balloon is
  40.0 m above the ground, a sandbag is dropped.
• Find the position and velocity of the sandbag at
  0.250 seconds and 1.00 seconds after release.
• How many seconds does it take to hit the ground?
• How fast is the bag going, just before it hits
  the ground?
• What is the greatest height that the bag reaches?

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4. If you drop a rock on the Earth and allow it
to fall an unknown height h, it reaches the
ground in 1.75 seconds. Now imagine that you drop
a rock from the same height h on Enceladus, one
of the moons of Saturn. You would find that the
rock reaches the ground in 18.6 seconds. What is
the acceleration due to gravity on Enceladus?