In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. What is the min rotational velocity in revolutions per second for which the ride is safe?

1.25 rev/s

Explanation:

N = mv^2/r (normal force )

f = μN  [Frictional force ]

f = mg

μN = mg

μ(mv^2/r) = mg

v = √(rg/μ)

min rotational velocity

v = √(rg/μ) = √(2.5 * 9.8/0.40) =  7.83 rad/sec

=  7.83/2π =  1.25 rev/s

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

i sometimes feel that way too. i feel that i should hurt someone because they hurt me, but i wouldnt do it. that would make things so much worse i have so much experience with this stuff

explanation: