Strong alien you got there good luck bud you never asked a question
Answer:
a)
, b) 
Explanation:
a) The magnetic force experimented by a particle has the following vectorial form:

The charge of the electron is equal to
. Then, cross product can be solved by using determinants:

The magnetic force is:

b) The charge of the proton is equal to
. Then, cross product has the following determinant:

The magnetic force is:

The law of motion that is being described in this scenario is Friction. Friction between the skate and the ice is what's moving the skater forward.
Answer:
Solution given:
velocity=40cm/s
wave length=5cm
we have
frequency =velocity/wavelength=40/5=8hertz.
the frequency of the <u>wave</u><u> </u><u>i</u><u>s</u><u> </u><u>8</u><u> </u><u>h</u><u>e</u><u>r</u><u>t</u><u>z</u><u>.</u>
KE = 1/2 * m * v2
We have to rearrange this so the subject is mass. (because the question asks for the mass of the object) :
Mass = (2 * KE) / v
Now input the values into this equation to get your answer :
Mass = (2 * KE) / v
Mass = (2 * 480) / 8
Mass = 960 / 8
Mass = 120