Ans is <span>I. Flowing groundwater that dissolves rock , such as limestone</span>
If the box is moving at constant velocity, net force must be zero, so:
F + fr = 0
fr = -F
<u>fr = -40 N</u>
Answer:5000000000hertz
Explanation:
Wavelength=6cm=6/100 m=0.06m
Frequency=velocity/wavelength
Frequency=(3×10^8)÷0.06
Frequency=5000000000 hertz