I tried using 10^-10 as the power emitted (got that from a website) and this is what I did:
I= 10^-10/ 4pi*3^2
I= 8.8*10^-13
That was wrong, so I'm really at a loss here.
Homework Statement
What is the sound intensity of a whisper at a distance of 3.0 m, in W/m^2 ?
What is the corresponding sound intensity level in dB?
Homework Equations
I=P/4*pi*r^2
The Attempt at a Solution
I tried looking up what the power of a whisper was and I can't find...
oh! The equation I have for work is W=Fx, but all that is given to me is two velocities and a mass. Force is m*a so w=m*a*x. I guess I'm still at a loss here.
Homework Statement
A 55 g particle is moving to the left at 27 m/s. How much work must be done on the particle to cause it to move to the right at 41 m/s? Answer in joules
Homework Equations
The Attempt at a Solution
27-(-41)=68 , 68*55= 3750
the units here are grams m/s. I...
Homework Statement
A 1.4 kg book is lying on a 0.80 m-high table. You pick it up and place it on a bookshelf 2.2 m above the floor.
1) How much work does your hand do on the book?
2.) How much work does gravity do on the book? [solved]
Homework Equations
Force*displacement=work...
ok. The work energy theorem is basically saying that since energy is always conserved, something had to provide energy and its done through work. So in less words it is the relationship between the work done and the change in energy.
I think gravity is doing most of the work by pulling the...
Homework Statement
You are a member of an alpine rescue team and must get a box of supplies, with mass 2.20 kg, up an incline of constant slope angle 30.0 degrees so that it reaches a stranded skier who is a vertical distance 2.80 m above the bottom of the incline. There is some friction...
Honestly, I had no idea what I was doing. I tried looking at how someone solved the same problem with different numbers and just plugged my numbers in but it didn't work.
Homework Statement
A 4.6×104 kg locomotive, with steel wheels, is traveling at 14 m/s on steel rails when its engine and brakes both fail. The coefficient of friction is 1.6×10−3.
1.) How far will the locomotive roll before it comes to a stop?
Answer in meters using two significant...
Quick question about forces!!!
Homework Statement
A skier is sliding down a 15 degree slope. Friction is not negligible. Identify all forces on the skier.
Homework Equations
n/a
The Attempt at a Solution
The choices are: Tension, Kinetic Friction, Weight, Static Friction...