downward force then reaction if you mean what forces
C. High-visibility clothing is important to wear in areas with moving vehicles
Answer:
Frequency is 
Explanation:
Distance between source 1 from the receiver , 
Distance between source 2 from the receiver , 
Now ,
Path difference , 
We know, for constructive interference path difference should be integral multiple of wavelength .
Therefore, 
It is given that n = 1,
Therefore, 
Frequency can be found by , 
Hence, this is the required solution.
Answer:
Explanation:
A proton and electron are moving in the positive x direction, this shows that their velocity will be in the positive x direction
V = v•i
Magnetic field Is the positive z direction
B = B•k
A. For proton.
Proton has a positive charge of q
Direction of force on proton
Force is given as
F = q(v×B)
F = q( v•i × B•k)
F = qvB (i×k)
From vectors i×k = -j
F = -qvB •j
Then, for the positive charge, the force will act in the negative direction of the y-axis
B. For electron
Electron has a negative of -q
Direction of force on proton
Force is given as
F = q(v×B)
F = -q( v•i × B•k)
F = -qvB (i×k)
From vectors i×k = -j
F = --qvB •j
F = qvB •j
Then, for the negative charge, the force will act in the positive direction of the y-axis