# Motion in two dimensions and gravitation, Physics and scientific help

Question description

(8 points)

Score

1.
During a medieval siege of a castle, the attacking army uses a
trebuchet to hurl heavy stones at the castle walls. If the trebuchet launches
the stones with a velocity of +30.0 m/s at an angle of 50.0°, how long does it
take the stone to hit the ground? What is the maximum distance that the trebuchet
can be from the castle wall to be in range? How high will the stones go? Show

(8 points)

Score

2.
A 70.0 kg astronaut is training for accelerations that he will
experience upon reentry. He is placed in a centrifuge (r = 10.0 m) and spun at a constant angular velocity of 16.3 rpm.
a.
What is the angular velocity of the centrifuge in rad/s?
b.
What is the linear velocity of the astronaut at the outer edge of the
centrifuge?
c.
What is the centripetal acceleration of the astronaut at the end of the
centrifuge?
d.
How many g’s does the
astronaut experience?
e.
What is the centripetal force and net torque experienced by the
astronaut? Give magnitudes and directions.
Show your
work.

(9 points)

Score

3.
An astronaut lands on an alien planet. He places a pendulum (L = 0.200 m) on the surface and sets it
in simple harmonic motion, as shown in this graph.
[img width=”354″ height=”253″ src=”file:///C:/Users/Spare/AppData/Local/Temp/msohtmlclip1/01/clip_image002.jpg” v_shapes=”_x0000_i1025″> NUMBER 1Answer the
following questions:
a.
What is the period and frequency of the pendulum’s motion?
b.
How many seconds out of phase with the displacements shown would graphs
of the velocity and acceleration be?
c.
What is the acceleration due to gravity on the surface of the planet in
m/s2? Determine the number of g-forces.

Show any
necessary calculations.

Score

1.  Explain how Einstein’s
contribution to understanding the force between the earth and the moon differed
from Newton’s.
(9 points)

Score

2.
Earth’s mass. Estimate the gravitational field on the surface of Saturn
compared to that on the Earth. Show your work.

Score

1.  An experiment was devised to
investigate the effects on the temperature of a cup of coffee when cream is
added at different time intervals. Hot and cold water were used instead of
coffee and cream. First, a container of water heated to 80°C was allowed to sit
for 15 minutes. Its temperature was measured at regular intervals. Next,
similar temperature measurements were taken for 15 minutes on a new container
of heated water, but this time some cold water was added after the 2-minute
reading. Finally, the procedure was repeated except that for this last test,
the cold water was added after the 12-minute reading. The resulting recorded
temperatures were plotted on the graph shown here. NUMBER2

Based on the information given here,
·
What question was asked in the experiment?
·
What was the hypothesis, expressed as an if-then statement?
·
What were the independent and dependent variables?
·
What was the control in the experiment?
·
Were there any sources of error in the experiment? If so, what?
·
What could you conclude from the data?
(9 points)

Score

2.
Compare and contrast deductive reasoning and inductive reasoning. Based
experiment:
·
What are the qualities of deductive reasoning?
·
What are the qualities of inductive reasoning?
·
Throughout the history of physics, when did these types of reasoning
come into play?
·
Provide one example of a physicist who used deductive reasoning, one
who used inductive reasoning, or one who used both.
(7 points)

Score

3.  The data in Light-Duty Vehicles
(1975–2006) show the efficiency of light-duty vehicles from 1975 (leftmost
point of the connected line) to 2006 (rightmost point of the connected line).
Each point represents a year in chronological order from the left end to the
right.

Data
http://www.sightline.org/images/blog-2008/Mileage-horsepower-EPA-600.gifNUMBER3
Look at
the graph carefully and answer the following questions:
·
What generalizations can you make about changes in fuel efficiency
(miles per gallon, MPG) over the course of the study?
·
What generalizations can you make about changes in engine performance
(horsepower) over the course of the study?
·
What generalizations can you make about changes in vehicle efficiency
(horsepower multiplied by MPG) over the course of the study?