(a) Find the charge on a baseball, thrown at 35.0 m/s perpendicular to the Earth’s $5.00\times 10^{-5}\text{ T}$ field, that experiences a 1.00-N magnetic force. (b) What is unreasonable about this result? (c) Which assumption or premise is responsible?

Video Transcript

This is College Physics Answers with Shaun Dychko. The force on this baseball is found using F equals the charge times the baseball speed times the magnetic field strength, and we can solve for q by dividing both sides by VB. So q is F over VB. So that’s one Newton divided by 35 meters per second times five times ten to the minus five Tesla, which gives 571 coulombs. Now such a large charge would repel itself off of such a small object, and it’s a very big number. Typical static shocks involve about five microcoulombs which is a piece of information I found from Wikipedia. So the one Newton force is very overstated and the baseball will likely experience a force much much less than that.