You drop 12 balls off of a platform that is an unknown distance above the ground and measure the time it takes for the ball to fall to the ground. how far above the ground is the platform? give a range for this answer that you can be 95% sure that the true distance lies within. assume that g = 9.80 m/s2. all times are given in seconds.

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

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

Apotter's wheel moves uniformly from rest to an angular speed of 0.20 rev/s in 32.0 s. (a) find its angular acceleration in radians per second per second. rad/s2 (b) would doubling the angular acceleration during the given period have doubled final angular speed?