Download Freefall Worksheet

Freefall Worksheet
Gravity Facts
• Gravity is not down - it is
together!
• Weightlessness does not exist
because one is in space; it exists
because one is
falling! Space has gravity just
like everywhere else, however,
there are no fixed
objects to hold against to keep
from falling.
• Antigravity doesn't exist.
Gravity is always attractive,
always a "together" force.
• Black holes don't suck
everything into them, unless the
object is falling toward them
in the first place. If the sun were
converted into a black hole, the
Earth would
continue in its orbit unperturbed.
• Heavier objects don't fall faster!
The speed of free fall is
consistent over the surface
of the Earth.
• Astronauts on the moon were
not weightless! The moon has
gravity much like the
Earth, however, since the moon is
less massive, the gravitational
pull is smaller.
The astronauts were pulled to the
moon with about 1/6th the force
of gravity on
Earth.
• Galileo probably didn't drop
cannonballs from the Leaning
Tower of Pisa. He most
likely experimented in another
location and with other items.
• Newton probably wasn't hit on
the head by an apple. He might
have had the idea
for extending the realm of gravity
to the heavens by watching an
apple fall. If so, he
was likely in the safety of his
study looking out a window. (He
was a fastidious man
in many ways, and it's hard to
imagine him lounging around in
an orchard.)
• Gravity is universal. All objects
in the universe are affected by all
other objects in the
universe. The farther two items
are from their centers, the weaker
the gravitational
force.
• Gravity affects time and space.
Moving of masses in the universe
warps time and
space and creates gravity waves.
• Since gravity pulls things
together, the most efficient shape
for an object is a sphere.
This way gravity pulls on all parts
of the whole equally.
Work the problems using the following equations and don’t forget to give your answer using the correct
number of significant figures. Draw a box around your answers.
g = 9.81 m/s2
v=gt
d = ½ g t2
1. I drop a penny from the top of the tower at the front of Fort Collins High School and it takes 1.85 seconds
to hit the ground. Calculate the velocity in m/s after 1.10 seconds of freefall and calculate the velocity at
impact in mi/hr.
2. If I drop a watermelon from the top of one of the tower dorms at CSU, and it takes 3.34 seconds to hit the
ground, calculate how tall the building is in meters and then convert into feet.
3. You are walking in Paris alongside the Eiffel Tower and suddenly a croissant smacks you on the head
and knocks you to the ground. From your handy dandy tourist guidebook you find that the height of the
Eiffel Tower is 300.5 m. If you neglect air resistance, calculate how many seconds the croissant dropped
before it tagged you on the head.
4. During the latter part of your European vacation, you are hanging out at the beach at the gold coast of
Spain. As you are laying in your chaise lounge soaking up the warm Mediterranean sun, a large glob of
seagull poop hits you in the face. Since you got an “A” in ICPE you are able to estimate the impact
velocity at 98.5 m/s. Neglecting air resistance, calculate how high up the seagull was flying when it
pooped.
5. If you were to throw a large log over the edge of the Grand Canyon and it took 5.65 seconds to hit the
ground, calculate the velocity of the log at impact in m/s and calculate the distance the log fell in feet.
Acceleration is the rate of change in the speed of an object. To determine the rate of acceleration,
you use the formula below. The units for acceleration are meters per second per second or m/s2.
A positive value for acceleration shows speeding up, and negative value for acceleration shows
slowing down. Slowing down is also called deceleration.
The acceleration formula can be rearranged to solve for other variables such as final speed (v2) and
time (t).
EXAMPLES
1. A skater increases her velocity from 2.0 m/s to 10.0 m/s in 3.0 seconds. What is the skater’s
acceleration?
Looking for
Acceleration of the skater
Given
Beginning speed = 2.0 m/s
Final speed = 10.0 m/s
Change in time = 3 seconds
Relationship
Solution
The acceleration of the skater is 2.7 meters per second
per second.
2. A car accelerates at a rate of 3.0 m/s2. If its original speed is 8.0 m/s, how many seconds will it
take the car to reach a final speed of 25.0 m/s?
Looking for
The time to reach the final speed.
Given
Beginning speed = 8.0 m/s; Final speed =
25.0 m/s
Acceleration = 3.0 m/s2
Relationship
Solution
`
The time for the car to reach its final speed is 5.7
seconds.
1. While traveling along a highway a driver slows from 24 m/s to 15 m/s in 12 seconds. What is
the automobile’s acceleration? (Remember that a negative value indicates a slowing down or
deceleration.)
2. A parachute on a racing dragster opens and changes the speed of the car from 85 m/s to 45 m/s
in a period of 4.5 seconds. What is the acceleration of the dragster?
3. The table below includes data for a ball rolling down a hill. Fill in the missing data values in the
table and determine the acceleration of the rolling ball.
Time (seconds)
Speed (km/h)
0 (start)
0 (start)
2
3
6
9
8
10
15
Acceleration = ___________________________
4. A car traveling at a speed of 30.0 m/s encounters an emergency and comes to a complete stop.
How much time will it take for the car to stop if it decelerates at -4.0 m/s2?
5. If a car can go from 0 to 60 mi/hr in 8.0 seconds, what would be its final speed after 5.0 seconds
if its starting speed were 50 mi/hr?
6. A cart rolling down an incline for 5.0 seconds has an acceleration of 4.0 m/s2. If the cart has a
beginning speed of 2.0 m/s, what is its final speed?
7. A helicopter’s speed increases from 25 m/s to 60 m/s in 5 seconds. What is the acceleration of
this helicopter?
8. As she climbs a hill, a cyclist slows down from 25 mi/hr to 6 mi/hr in 10 seconds. What is her
deceleration?
A list of the gravitational accelerations at the surfaces of each of the planets in our solar system. Values
are listed as multiples of g on Earth.Note: The "surface" is taken to mean the cloud tops of the gas
giants (Jupiter, Saturn, Uranus and Neptune).
Planet
Gravitational Acceleration (multiples of g on Earth)
Mercury
0,376
Venus
0,903
Earth
1
Mars
0,38
Jupiter
2,34
Saturn
1,16
Uranus
1,15
Neptune
1,19
Pluto
0,066
Mass
Weight
1. is a measure of how much matter there is in
an object.
1. is the force with which the Earth attracts an
object.
2. is measured in kilograms.
2. is measured in newtons
3. is the same on any planet.
3. is different on different planets.
4. is a scalar.
4. is a vector.
Now, we have said that the value of g is approximately 9,8m⋅s−2 on the surface of the Earth. The actual value
varies slightly over the surface of the Earth. Each planet in our Solar System has its own value for g. These
values are listed as multiples of g on Earth in Table
Differences between Mass and Weight
Mass is measured in kilograms (kg) and is the amount of matter in an object. An object's mass does not
change unless matter is added or removed from the object.The differences between mass and weight can
be summarized in the above table:
1. A bag of sugar has a mass of 1kg. How much does it weigh:
1. on Earth?
2. on Jupiter?
2. Neil Armstrong was the first man to walk on the surface of the Moon. The gravitational
acceleration on the Moon is 16 of the gravitational acceleration on Earth, and there is negligible
gravitational acceleration in outer space. If Neil's mass was 90kg, what was his weight:
1. on Earth?
3. in outer space?
2. on the Moon?
3. A monkey has a mass of 15kg on Earth. The monkey travels to Mars. What is his mass and
weight on Mars?
4. Determine your mass by using a bathroom scale and calculate your weight for each planet in
the Solar System, using the values given in Table