Answer:
Explanation:
Since the Earth's magnetic field is perpendicular to your direction of motion, the strength of the magnetic force exerted on your head is given by:
where:
is the charge on your head
is the speed at which you are moving
is the strength of the magnetic field of the Earth
By substituting these numbers into the equation, we find the strength of the magnetic force:
Gravity is directly proportional to the product of the two. Masses and inversely proportional to the square distance between the two masses.
The object would have a centripetal acceleration <em>a</em> of
<em>a</em> = (12 m/s)² / (0.7 m) ≈ 205.714 m/s²
so that the required tension in the string would be
<em>T</em> = (0.5 kg) <em>a</em> ≈ 102.857 N ≈ 100 N
(rounding to 1 significant digit)
