The Burj Khalifa is the tallest building in the world with a height of 0.828 km. On his delivery on Christmas Eve, Santa Claus accidentally bumps into the Burj Khalifa and drops a toy from the very top of the building. What is the magnitude of the velocity (in m/s) of the toy 0.642 km from above the ground? Neglect air resistance. g=9.81m/s2

70 give a real life example showing how sensory neurons work with the motor neurons

In the circuit, the switch s has been open for a long time and r = 125 kohm. it is then suddenly closed. (a) determine the time constant before the switch is closed. s (b) determine the time constant after the switch is closed. _ s (c) let the switch be closed at t = 0. find the current in the switch as a function of time. (use t for time. express your answer in milliamps and seconds.) i(t) =_

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?