1.) When a charged particle moves at an angle of 15° with respect to a magnetic field, it experiences a magnetic force of magnitude F. At what angle (less than 90°) with respect to this field will this particle, moving at the same speed, experience a magnetic force of magnitude 1.8F?

2.) A 45-m length of wire is stretched horizontally between two vertical posts. The wire carries a current of 74 A and experiences a magnetic force of 0.15 N. Find the magnitude of the earth's magnetic field at the location of the wire, assuming the field makes an angle of 50.0° with respect to the wire.