Q1. A boat crosses a river of width 115 m in which the current has a uniform speed of 1.39 m/s. The pilot maintains a bearing (i.e., the direction in which the boat points) perpendicular to the river and a throttle setting to give a constant speed of 2.38 m/s relative to the water.
What is magnitude of the speed of the boat relative to a stationary shore observer?
Answer in units of m/s
Q2. A 1,720 Hz pure tone is played on a stereo in an open field. A person stands at a point that is 4 m from one of the speakers and 4.4 m from the other. Does the person hear the tone? Explain.
Q3. The Sun's diameter is 1.4 106 km and it is 1.5 108 km away. How huge is the image of the Sun on the film used in a camera with the following lens?