Ch3_1
New Problems
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Make sure to calculate your answers in SI units unless specified otherwise .
1) The
x
-component of a velocity vector is -
m/s
and the
y
-component is
m/s
. What is the magnitude of the velocity
(sheet 3,4 and 5)
?
2) The magnitude of a velocity vector is and its direction is
degrees
(measured counter clockwise from the positive
x
-axis). What is the
y
-component
(sheet 3,4 and 5)
?
3) The
x
-and
y
-components of two vectors
A
and
B
in the notation (
x, y
) are (, ) for
A
and (-6, ) for
B
in arbitrary units. What is the direction of the vector
C
= (
A
-
B
) measured as an angle between the vector
C
and the positive
x
-axis in counter clockwise direction
(sheet 6
- convince yourself with the graphical "head to tail" method that your result makes sense,
see sheet 7,8
; such a graphical evaluation will be required in midterm 1 ) ?
4) A person runs on a slowly moving trailer with
m/s
toward the back end of the trailer. What is the velocity of the person relative to the ground if the trailer has a velocity of
m/s
(sheet 13,14,14')
? The direction in which the trailer moves is the positive
x
-axis.
5) A person in a rowboat crosses a river which flows with
km/hr
. The person rows with maximum velocity of
km/hr
relative to the water (measured while rowing on a still lake) and heads the boat straight across the river - along a line at 90
degrees
with respect to the river shore pointing to a point on the opposite shore. How far downstream from this point in
km
does the person reach the opposite shore if the river is
km
wide
(sheet 13,
similar to
15,
but figure on the right on
sheet 16"'
is relevant
)
?
6) A person in a rowboat crosses a river which flows with
km/hr
. The person rows with maximum velocity of
km/hr
relative to the water (measured while rowing on a still lake) and wants to reach the opposite shore directly across from the start point - along a line at 90
degrees
with respect to the river shore . At what angle with respect to this line does the person have to point the boat
(sheet 15 to 16")
? Indicate with a negative (positive) sign whether the boat has to be pointed upstream (downstream).
Once you have submitted your answers for grading by clicking the grade button, you
cannot resubmit answers
for the same Problem Set--you must use the 'New Problems' button first.