1. A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river. The river is 800 m wide.

a. In which direction should the motorboat head in order to reach a point on the opposite bank directly east from the starting point? (The boat's speed relative to the water is 4.2 m/s.)Express your answer in degrees.

b. What is the magnitude of the velocity of the boat relative to the earth?Express your answer in meters per second.

c. How much time is required to cross the river?Express your answer in seconds.

2. A model of a helicopter rotor has four blades, each of length 3.9 mfrom the central shaft to the blade tip. The model is rotated in a wind tunnel at a rotational speed of 550 rev/min.

a. What is the linear speed of the blade tip?Express your answer in meters per second.

b. What is the radial acceleration of the blade tip expressed as a multiple of the acceleration due to gravity, g?Express your answer as a multiple of g.