An ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at 12.8 m/s2 . at t1 the rocket engine is shut down and the sled moves with constant velocity v for another t2 s. the total distance traveled by the sled is 5.37 × 103 m and the total time is 97.7 s. find t1.

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

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.

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.