- #1

TRVSA

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## Homework Statement

A ball of mass m is attached to a rope of length L which has one end at the origin; the ball moves in a horizontal circle at constant speed v0 on a frictionless plane; the velocity is always at 90◦ to the rope. The ball has a charge q, and moves in a constant magnetic field which is directed vertically B⃗ = B0kˆ. At the time illustrated, the ball is at location ⃗r = L cos θˆı + L sin θˆ, with velocity ⃗v = −v0 sin θˆı + v0 cos θˆ.

- Assume that q = 3.0[C], B0 = 1.0[T], v0 = 5.0[m/s], m = 4.0[kg], and L = 2.0[m], what charge would have to be fixed at the origin in order the tension in the rope became 0?

## Homework Equations

T = mv0^2/L + qv0B0

## The Attempt at a Solution

I set T to 0, plugged in the values given and tried to solve for q.