Very dear university colleagues ... perform the
following problems:
practice
- The
following passages are excerpts from "The Long, Lonely Leap" by
Captain Joseph W. Kittinger Jr. USAF as they appeared in National
Geographic magazine. It is the story of his record-setting, high
altitude parachute jump from a helium balloon over New Mexico on
16 August 1960.
An hour and thirty-one minutes after launch, my
pressure altimeter halts at 103,300 feet. At ground control the radar
altimeters also have stopped on readings of 102,800 feet, the figure that we
later agree upon as the more reliable. It is 7 o'clock in the morning, and I
have reached float altitude.
At zero count I step into space. No wind
whistles or billows my clothing. I have absolutely no sensation of the
increasing speed with which I fall.
Though my stabilization chute opens at 96,000
feet, I accelerate for 6,000 feet more before hitting a peak of 614 miles an
hour, nine-tenths the speed of sound at my altitude. An Air Force camera on the
gondola took this photograph when the cotton clouds still lay 80,000 feet
below. At 21,000 feet they rushed up so chillingly that I had to remind myself
they were vapor and not solid.
Verify the speed claim of the author. (At this
altitude g = 9.72 m/s2.)
2 2 . A basketball dropped from rest 1.00 m
above the floor rebounds to a height of 0.67 m. Assuming the ball is not
moving horizontally, calculate its velocity…
a.
just
before it hit the floor on the way down and
b.
just
after it left the floor on the way up.
If the ball is in contact with the floor for
0.10 s determine its acceleration…
- on the way down,
d.
while
it is contact with the floor, and
e.
on the way up.
3 3. A diver jumps from a 3.0 m
board with an initial upward velocity of 5.5 m/s. Determine…
.
the
time the diver was in the air
a.
the
maximum height to which she ascended
b.
her
velocity on impact with the water
4
4. Sketch the following graphs of
motion for an object thrown straight up.
c.
displacement-time
d.
velocity-time
e.
acceleration-time
Deliver them on a worksheet next Thursday
A fraternal hug