4-A particle moves in a helical path such that its position in cylindrical coordinate given by R=b Find the speed and the magnitude of the acceleration as a function of t.

VCM-2 As Khanh is driving her car along a straight road with a constant speed, she passes over a series of hills and dips. Each dip and hill has a radius of curvature of 250m She has a 5.00kg package sitting on a scale on the seat beside her. On one stretch of the road she passes thru a dip and then over a hill as shown below. a) Use the velocity vectors shown for V1 and V2, the velocities just before and just after the bottom of the dip, to show the direction of AV, the change in velocity in going thru the bottom of the dip. R=250m Car at the top of the hill. Car at the bottom of the dip. V2 b) Apply Fnet-ma to write symbolic equations for the package when it is in the car at the bottom of the dip. Include all forces on the package. If something equals zero, show it here, otherwise use no numbers in this step. R=250m

Current Attempt in Progress An astronaut is rotated in a horizontal centrifuge at a radius of 3.90 m. (a) What is the astronaut's speed if the centripetal acceleration has a magnitude of 7.50g? (b) How many revolutions per minute are required to produce this acceleration? (c) What is the period of the motion? (a) Number i Units (b) Number i Units (c) Number i Units

4. Given the acceleration as a function of the angle theta, a = 6.5 sin θ + 2.3cos θ i. Find the optimal angle, so the acceleration is maximum. ii. Find the value of the maximum acceleration.