Atennis ball is hit at an angle of 20° to the horizontal with a velocity of 21 m/s. what is its velocity in the y-direction? a. 7.2 m/s b. 19.7 m/s c. 6.8 s d. 0.9°

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.