A rail gun uses electromagnetic forces to accelerate a projectile to very high v

Question

A rail gun uses electromagnetic forces to accelerate a projectile to very high velocities. The basic mechanism of acceleration is relatively simple and can be illustrated in the following example. A metal rod of mass 30.0 g and electrical resistance 0.500 rests on parallel horizontal rails that have negligible electric resistance. The rails are a distance L = 9.00 cm apart. (Figure 1) The rails are also connected to a voltage source providing a voltage of V = 5.00 V .
The rod is placed in a vertical magnetic field. The rod begins to slide when the field reaches the value B = 0.163 T . Assume that the rod has a slightly flattened bottom so that it slides instead of rolling. Use 9.80 m/s2 for the magnitude of the acceleration due to gravity.

Find s, the coefficient of static friction between the rod and the rails.

Explanation / Answer

Here

current in the rod , I = V/R

I = 5/.50 = 10 A

for the coefficient of static friction s

s * m * g = B *I*L

s = B*I*L/(mg)

s = 0.163 * 10 * 0.09/(0.030 * 9.8)

s = 0.50

the the coefficient of static friction between the rod and the rails is 0.50

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.