Question1
A long solenoid has 100 turns/cm and carries a current i. An electron moves within the solenoid in a circle of radius 0.021 cm perpendicular to the axis of the solenoid. The speed of electron is 0.042c (c is the speed of light).What is the current i?
Question2
Assume a crate of mass 8.8 kg is placed on the plank at a distance x = 4.5 m from the left end. If the plank has a mass of 12 kg, find the forces exerted by the two supports on the plank.
Question3
A ball is thrown straight down with an initial velocity of 15 m/s. At accurately the same time, a second ball is thrown straight down from a position 5 m straight below the first ball. The initial velocity of the second ball is 2 m/s. How long after being thrown will the balls collide?