Answer for Ch. 30, 17P

Answer stated in problem description.

Answer for Ch. 30, 19P

Answer stated in problem description.

Answer for Ch. 30, 26P

B points upward.

Answer for Ch. 30, 38P

3.2  mN toward the long wire

Answer for Ch. 30, 39P

a) F points right.

Please note that an answer twice as large will be obtained if the currents are considered to flow past the projectile. Actually the current is shunted away from the remaining part of the rail by the projectile; the field is then that at the end of two semi-infinite currents; i.e. the geometry of Problem 18P in Ch. 30, resulting in a field strength of one-half that of infinitely long currents.

b) v_F = 2.3 km/s.