fisica1-youn-e-freedman-exercicios-resolvidos

3.34: a) a
2
rad
= ( 3 m/s) /(14 m) =
0.643 m/s
2
, and
a
tan
= 0.5 m/s
2
. So,
2 2
2 2 2
2
a = ((0.643 m/s ) + (0.5 m/s ) )
1/ = 0.814 m/s , 37.9°
to the right of vertical.
b)
3.35: b) No. Only in a circle would a
rad
point to the center (See planetary motion in
Chapter 12).
c) Where the car is farthest from the center of the ellipse.
3.36: Repeated use of Eq. (3.33) gives a) 5 .0 = m/s to the right, b) 16.0 m/s to the left,
and c) 13 .0 = m/s to the left.
3.37: a) The speed relative to the ground is 1 .5 m/s + 1.0 m/s = 2.5 m/s , and the time is
35 .0 m/2.5 m/s = 14.0 s. b) The speed relative to the ground is 0.5 m/s, and the time is
70 s.
3.38: The walker moves a total distance of 3.0 km at a speed of 4.0 km/h, and takes a
time of three fourths of an hour (45.0 min). The boat’s speed relative to the shore is 6.8
km/h downstream and 1.2 km/h upstream, so the total time the rower takes is
1.5 km 1.5 km
+ = 1.47 hr = 88 min.
6.8 km/h 1.2 km/h
3.39: The velocity components are
− 0 .50 m/s + (0.40 m/s)/ 2east and (0.40 m/s)/
for a velocity relative to the earth of 0.36 m/s, 52 .5°
south of west.
2 south,