fisica1-youn-e-freedman-exercicios-resolvidos

v
3.4: iˆ
2
= 2bt + 3ct
ˆj
y-components are equal; in terms of the parameters, this time is
3.5: a)
. This vector will make a 45°
-angle with both axes when the x- and
2 b 3c
.
( −170
m s) − (90 m s)
2
b) a
x, ave
=
= −8.7
m s ,
(30.0 s)
( 40 m s) − (110 m s)
2
a
y, ave
=
= −2.3 m s .
(30.0 s)
2
2
(
−8.
7
2
2
2
−2.3
c) −8.7
m s ) + ( − 2.
3 m s ) = 9.0 m s , arctan ( ) = 14.8° + 180°
= 195°
.
2
2
x
=
y
3.6: a) a ( 0.45 m s )cos31.0°
= 0.39 m s , a = (0.45 m s )sin 31.0°
= 0.23 m s ,
so v = 2.6 m s + (0.39 m s )(10.0 s) = 6.5 m s and
x
v = −1.8
m s + (0.23 m s )(10.0 s) = 0.52 m s .
y
2
2
b) = (6.5 m s) + (0.52 m s) = 6.48 m s
horizontal.
c)
2
2
.52
v , at an angle of ( ) = 4. 6°
2
0
arctan above the
6. 5
2