B. only its velocity should change
If only 1 option is correct then it is (D)
All the others can also make one component negative, all depends how u measured the angle.
all the best
8500 Hz and Longitudinal
Speed = frequency x wavelength
Speed of sound at 20 degrees Celsius is approximately 340 m/s
Answer:
1. Emma standing on top of mountain
Since she is at the rest position and at some height from the ground so here energy is due to gravitational potential energy
So we have
gravitational potential energy

2. Emma jumping down from mountain top
Due to free fall Emma will start moving with some speed in downwards direction so here we have

motion energy
3. tension in rope at Emma’s lowest position
Due to stretch in the rope here position come to the lowest end and speed comes to zero so whole energy is converted into elastic potential energy

elastic potential energy
4. Emma bouncing back
Due to bouncing back she will again have its kinetic energy with some speed upwards

motion energy