A 20kg dog and a 60kg dog are placed at the opposite ends of an 8-meter-long light beam. Where should the fulcrum be placed?

As a result of his observations, Ole Roemer concluded that eclipses of Io by Jupiter were delayed by 21 min and 22 second, during a six-month period as the Earth moved from the point in its orbit where it is closest to Jupiter to the diametrically opposite point where it is farthest from Jupiter. Using the value 1.50×108 km as the average radius of the Earth’s orbit around the Sun, calculate the speed of light from these data. (Give your answer in scientific notation using "m/s" (meter per second) as unit).

With an analyzer between the polarizer and the light sensor, with the polarizer at zero degree and the analyzer at ninety degrees has an illuminance was 1505.28 lux. Then another polarizer is inserted between the analyzer. The transmission axis of the added polarizer is 45 degrees. What would you expect the illuminance measured by the light sensor to be?

A group of students was at a graduation party in one student’s backyard.  The star of the basketball team, who is very tall, arrived late.  As he walked across the back yard his head bumped into one light in a strand of part light.  All of a sudden all of the party lights went out.  Explain why all of the lights in the strand went out when one light was bumped.

Unpolarized light passes through a single polarizer. Of the 100% of the light that made it through the first polarizer, how much will make it through... another polarizer, angled 30° to the first one, and then yet another polarizer, angled a further 30°. a vacuum. another polarizer, angled 30° to the first one. another polarizer, angled 90° to the first one. another polarizer, angled 45° to the first one. another polarizer, angled 45° to the first one, and then yet another polarizer, angled a further 45°. 1. 100% 2. 75% 3. 66.67% 4. 56.25% 5. 50% 6. 33.33% 7. 25% 8. 12.5% 9. 0%

A flashlight is used to propel an 85 kg reflective load in space. If the flashlight emits 1W of light in a parallel beam for 1 hour, and the entire beam falls on the surface of the load, find how far the load will have moved at the end of the hour. Assuming it started at rest. (Hint: the force, mass, and acceleration are related through F=m*a; you should also use the physics equation relating position, velocity, and acceleration).

Light passes through two different polarizers. The first is aligned vertically, while the second is aligned horizontally. How much light makes it through the two polarizers?