Answer:
after 2 seconds its velocity is -20 m/s. after 3 seconds its velocity is -30 m/s. after 10 seconds its velocity is -100 m/s.
Explanation:
This is my answer.
The correct choice is
D. 22 Hz and 42 Hz.
In fact, the beat frequency is given by the difference between the frequencies of the two waves:

In this problem, the beat frequency is
, therefore the only pair of frequencies that gives a difference equal to 20 Hz is
D. 22 Hz and 42 Hz.
Answer:
a) 25.5°(south of east)
b) 119 s
c) 238 m
Explanation:
solution:
we have river speed
=2 m/s
velocity of motorboat relative to water is
=4.2 m/s
so speed will be:
a)
=
+
solving graphically

=4.7 m/s
Ф=
=25.5°(south of east)
b) time to cross the river: t=
=
=119 s
c) d=
=(2)(119)=238 m
note :
pic is attached
Answer:

Explanation:
q = Charge
r = Distance




The electric field is given by

The electric field at the aircraft is 