Eight
Remark
When you are using a circular radius, the formula to use is F = m*v^2/r. When the radius is created by a Magnetic force, the formula is F = q*v*B. These two forces are equal.
Formula
- mv^2/ r = q*v*B Divide both sides by v
- m*v/r = q*B
Givens
- v = 4920 m/s
- r = 17.5 cm = 0.175 m
- m = ?
- q = 1.6 *10^-19
- B = 0.0175 T
Solution
m*4920 / 0.175 = 1.6 * 10^-19 * 0.0175 Calculate the right and left sides.
m*28114 = 2.8*10^-21 Divide by 2811.4
m = 2.8^10^-21 / 28114
m = 9.96 * 10^-26
Answer C
Ten
Formula
F = q* v * B
Givens
q = 2*1.6 * 10^-19 = 3.2 * 10 ^ - 19
v = 35.6 km/s = 35600 km / s
B = 1.1 T
Solution
F = 3.2 * 10^-19 * 35600 * 1.1
F = 1.25 * 10^-14
Answer: C
