Answer:
the observed frequency will reduce but the wavelength will increase
Explanation:
As we know
fo = fs (v/(v-vs))
fo = observed frequency
vs = velocity of source
As per this equation,
When an observer moves away from the stationary source, the observed frequency reduces. Since the observer in the balloon is moving away from the source which itself is moving in opposite direction, the observed frequency will reduce.
Since wavelength = V/fs . The source frequency is unchanged but the velocity is increasing as it is moving in downward direction. Hence, the wavelength will increase
There would be no mass or weight and he would float away
first we make a U turn and travel towards home in t = 20 s
so the distance of home from initial position is


Now after picking up the book we travel back with speed 20 m/s
so again after t = 20 s the displacement is given as

so the net displacement is given as


so it will be displaced by total displacement 200 m
Work = Force times Distance
W = Fd
Given W = 750J, F = 125N;
750 = 125d
Solving for d:
d = 750/125
d = 6
The box moved a distance of 6 meters.
Factor out 8 and then facotr and u get
8/9(9x+1)(9x-1