The light gathering power of a reflecting telescope is directly related to the area of the primary mirror: Area = pi x d^2 / 4
(Where d is the diameter of the mirror)
Set up a fraction to compare the light gathering power of a 10- meter diameter (Keck) telescope with that of a human pupil. The human pupil has a diameter of about 5 millimeters. How many times more intense is the light gathered by a Keck telescope, than light gathered by the human eye.

Choose the most likely outcome of this scenario: jen decided to go bike riding without a helmet. while no one is around during her ride, she is thrown from her bike when her wheel goes into a pothole. she is not injured, but she is terrified to get back on her bike. what happens next? a. her physical health is affected even though she wasn't hurt. b. her mental and emotional health are affected because she is afraid to get back on her bike. c. her social health is affected because she is worried her friends saw the fall. d. her overall health is not affected at all by her fall.

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n