Aboat crosses a river of width 161 m in which the current has a uniform speed of 1.09 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 2.77 m/s relative to the water. what is the magnitude of the speed of the boat relative to a stationary shore observer? answer in units of m/s.

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Which of the following are not typically included in the periodic table? a. atomic mass b. element symbol c. isotopes d. number of electrons

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.