What is the mechanical advantage of this pulley system?

Apositive point charge q is fixed on a very large horizontal frictionless tabletop. a second positive point charge q is released from rest near the stationary charge and is free to move. which statement best describes the motion of q after it is released? assume q stays on the table

Jason and mia are both running in a race. as they approach the finish line, you being the physicist that you are decide to time how long it takes them to reach the end of the race. when you start your stop watch (you can take this as time t = 0 s) you notice that mia is an unknown distance d ahead of jason and both are moving with the same initial velocity v_0. you also notice that jason is accelerating at a constant rate of a_j, while mia is deaccelerating at a constant rate of -a_m. jason and mia meet each other for the first time at time t = t_1. at this time (t = t_1) jason's velocity is two times that of mia's velocity, meaning v_j (t_1) = 2v_m (t_1). a) draw the position vs. time graph describing mia's and jason's motion from time t = 0 to time t = t_1. clearly label your axes and initial conditions on your graph. b) draw the velocity vs. time graph describing mia and jason's motion from time t = 0s to time t = t_1. clearly label your axes and initial conditions on your graph. c) how long from when the stop watch was started at t = 0s did it take mia and jason to meet? express your answer in terms of know quantities v_0, a_m, and a_j. d) when the stop watch started at time t = 0s, how far apart, d, were mia and jason? express your answer in terms of know quantities v_0, a_m, and a_j.

Astone is dropped with no initial velocity from the top of a cliff and hits the ground a time of 3.9 s later. what is the height of the cliff, in units of meters? you may assume that air resistance is negligible. give the answer as a positive number question 15 a figure skater is rotating at a rate of 200 revolutions per minute. what is the angular speed, in units of rad/s? 200 o 20.9 12000 o 3.33