Recent content by BlueSkyy

Melting Ice With Aluminum?? Homework Statement How many grams of aluminum at 90 degrees C would have to be dropped into a hole in a block of ice at 0.0 degrees C to melt 10 g of ice? Homework Equations Q = (m)(c)(deltaT) c of aluminum = 0.9 c of ice = 2.1 c of water = 4.186 333.7...

Homework Statement The pitch of the sound from a racecar engine drops the musical interval of a fourth when it passes the spectators. This means the frequency of the sound after passing is 0.75 times what it was before. How fast is the racecar moving? 1. 61 m/s 2. 49 m/s 3. 72...

okay, that's what i was thinking, but i didn't know if i could use an equals sign since we were working with a proportion :) thank you!

no idea. this is kinda where i got stuck...

so the frequency is proportional to the square of the tension?

but this has nothing to do with the frequency, since L stays the same...

if L doubles, than T is quadrupled, right?

as L gets bigger, F gets bigger, right?

Homework Statement In order to decrease the fundamental frequency of a guitar string by 4%, by what percentage should you reduce the tension? Homework Equations f = sqrt [T/(m/L)] / 2L I believe that is the equation that relates frequency to tension... The Attempt at a Solution...

Thank you so much Retsam! That worked :D I didn't know I could use PE = 1/2 k x^2 for pendulums; now I know! Thank you!

Mechanical energy of a pendulum- I just can't get it! Homework Statement A pendulum of length 140 cm swings with an amplitude of 1.9 cm. Its mechanical energy is 5.7 mJ. What is the mechanical energy of the same pendulum when it swings with an amplitude of 3.7 cm? Homework Equations...

Homework Statement An experiment to determine the specific heat of a gas makes use of a water manometer attached to a flask (the figure below ). Initially the two columns of water are even. Atmospheric pressure is 1.4 x 10^5 Pa. After heating the gas, the water levels change to those shown...

Homework Statement A mountain climber is rappelling down a vertical wall (the figure below ). The rope attaches to a buckle strapped to the climber's waist 15 cm to the right of his center of gravity. If the climber weighs 770 N, find (a) the tension in the rope and (b) the magnitude and...

AH! I forgot! KE(rotational) = B 1/2 m (v^2) where B = 2/5 Thank you, I figured it out now~ :)

i kept "r" as a variable and came up with: 8.0766 + 0.1204 (r^2) (w^2) but the problem asks for a specific number ( _____ J) so I can't keep the variable "r" there... also, when they say total energy, do they mean total KE, since the ball is still in motion? I'm trying to use PE to solve for...