A skydiver jumps from a stationary helicopter and reaches a steady vertical speed. She then opens her parachute.
Which statement about the falling skydiver is correct?

A As her parachute opens, her acceleration is upwards.
B As she falls at a steady speed with her parachute open, her weight is zero.
C When she accelerates, the resultant force on her is zero.
D When she falls at a steady speed, air resistance is zero.

Acentrifuge in a medical laboratory rotates at an angular speed of 3,700 rev/min. when switched off, it rotates through 54.0 revolutions before coming to rest. find the constant angular acceleration (in rad/s2) of the centrifuge. your response is within 10% of the correct value. this may be due to roundoff error, or you could have a mistake in your calculation. carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s2