Answer to Question #292229 in Electricity and Magnetism for Qurbanova

Question

A ball with a mass of 1 gramme and a charge of 10^-8 C moves from point A whose potential is 600 V to point B whose potential is zero. What was the velocity of the ball at point A if at point B it is 20 cm/s?

Answer 1

Answer

Potential difference

$V_{AB}=600-0=600volts.$

Charge Q=$10^{-8}C$

Speed of B

$v_B=0.2m/s$

Using energy conservation

$QV_{AB}=0.5m(v_A^2-v_B^2)$

Putting all values

$v_B^2=\frac{10^{-8}\times600}{0.5\times0.001}+0.04\\=0.07\\v=0.26m/sec$