Recent content by tymartin

Homework Statement Suppose a revolving door at the bank is spinning around once every 4 seconds. As you walk through, you push on the door for 3 seconds, which increases the rotational speed so that it rotates once a second. What wat the rotational acceleration due to your push? Homework...

Homework Statement You need to open a heavy door that's 30 inches wide. Instictively, you push near the edge that's farthest from the hinges. If, instead, you had pushed at a point only 10 inches in from the hinges, how much harder would you have had to push to open the door at the same speed...

Homework Statement You're riding a fast spaceship going 7.52 x 107m/s and you turn on your flashlight. What's the speed of the light ray relative to the spaceship? What is its speed relative to the earth? Homework Equations The Attempt at a Solution Deeply confused

Homework Statement Suppose you want to measure the position of an electron to within 1 angstrom. If you also want to measure its momentum, how accurately can you do this if you don't want to mess up your measurement of its position? Homework Equations An angstrom is 1 x 10-10 The...

Homework Statement You're riding in a very fast train from Chicago to Detroit. In Chicago you set your watch to the correct time, but as you ride through downtown Detroit, you notice that your watch differs from the time shown on the clocks in the station! Are all the clocks in Detroit...

thanks for everyone's help

Homework Statement What is the rest mass energy of one mole of neutrons? Hint one mole is 6.02 x 1023 particles (avocado's number), and the neutron has mass m=1.675 x 10 -27 kg. Homework Equations The Attempt at a Solution I wasn't sure of the relationship between moles and...

Homework Statement A beam of sunlight with a wavelength of 500 nm strikes an ice floe at an angle of 66.5 If ice has an index of refraction n=1.31, at what angle is the beam refracted? Homework Equations Law of Refraction- n(i) sin 0(i)=n (r) 0 (r') The Attempt at a Solution I'm...

A string has a mass of 0.02 kg that's 25 m long. The wave has a frequency of 3 Hz. Find the amplitude, wavelength, and velocity of the wave and tension in the rope. Would really appreciate any help on this question. Having a terrible time with it.