Avisitor to a lighthouse wishes to determine the height of the tower. she ties a spool of thread to a small rock to make a simple pendulum, which she hangs down the center of a spiral staircase of the tower. the period of oscillation is 10.1 s. the acceleration of gravity is 9.8 m/s 2 . what is the height of the tower?

Imagine you are riding on a yacht in the ocean and traveling at 20 mph. you then hit a golf ball at 100 mph from the deck of the yacht. you see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph). now imagine you are aboard the hermes spacecraft traveling at 0.1c (1/10 the speed of light) past mars and shine a laser from the front of the ship. you would see the light traveling at c (the speed of light) away from your ship. according to einstein’s special relativity, how fast will a person on mars observe the light to be traveling? a) 0.1c (1/10 the speed of light) b) c (the speed of light) c)1.1c (c+0.1c)