Chapter 2, Problem 76P

About how fast would you have to be driving toward a red (A = 685 nm) stoplight for it to appear green (A=532 nm)? × 104 km/sec. For the red stoplight to appear green, the velocity would have to be VR =[

Bob has just finished climbing a sheer cliff above a level beach and wants to figure out how high he climbed. All he has to use is baseball, a stopwatch, and friend on the ground below with a long measuring tape. Bob is a pitcher and knows that the fastest he can throw the ball is about v_0= 34 m/s. Bob starts the stopwatch as he throws the ball, with no way to measure the ball’s initial trajectory, and he watches carefully. The ball rises and then falls, and after t_1= 0.510 s the ball is once again level with Bob. Bob cannot see we’ll enough to time when the ball hits the ground. Bob’s friend the measures that the ball hit the ground x= 127 m from the base of the cliff. How high above the beach was the ball when it was thrown? A projectile is launched from ground level with an initial speed of 45.5 m/s at an angle of 32.3 degrees above the horizontal. It strikes a target in the air 1.83 s later. What is the horizontal distance from where the projectile was launched to where it hits…

An athlete crosses a 28 meters wide river by swimming perpendicular to the water current at a speed of 1.1 m/s relative to the water. He reaches the opposite side at a distance of 42 meters downstream from his starting point. w = 28md = 42m vs = 1.1m/s What is the speed of the swimmer with respect to a freind at rest on the ground in m/s?