Ask Ravi

Holy shit, are you reading my mind? I was just thinking whether I should've bothered you with these. :ph34r:
 
1. A 4.00-kg particle moves along the x-axis. It's position varies with time according to

x= t + 2.0t^3,

where x is in meters and t is in seconds.

(a) Find the kinetic energy for any time t.

differentiate the equation once to get velocity

KE = 0.5 x MASS x (velocity)^2

(b.)What is the force acting on the particle at any time t?

differentiate again to get acceletartion

Force = MASS x ACCELERATION
c) How much power is being delivered to the particle at time t?

Power = force x velocity

(d.)Find the work done on the particle in the interval t=0 to t=2.00s.

work done = force x distance

In this casse since force is variable, you will have to integrate

force x distance, ie. (B)x(x= t + 2.0t^3)

from t=0 to t=2.00s.

(e) Show that the work-energy theroem is satified for the interval given in (d), that is, shpw that the change in kinetic energy is equaled to the work done on the particle.

calculate KE using (a), at t = 0, and t = 2, sibtract, it should be equal to (d)
 
2. A light, flexible, nonstretching cable is wrapped several times around a winch drum, a solid cylinder of mass 50kg and diameter 0.120m, which rotates about a stationary horizontal axis held by a frictionless bearing. The free end of the cable is pulled with a constant force of magnitude 9.0N for a distance of 2.0m. The cable unwinds without slipping, turning the cylinder as it does so. (a)Use the definition of the rotational inertia for a continuous body to show that the rotational inertia of the winch drum (or any solid cylinder) is I=1/2(MR^2), where M is the mass of the cylinder and R is its radius. [Let the mass element dm=ρdV=ρ(2'pie'rLdr).]


b.)If the cyclinder is initally at rest, find its final angular speed and the final speed of the cable.


C) Calculate the net torque (magnitude and direction) in the cylinder about its axis of roation.


(d)What is the angular displacement of the cylinder as the cable is unwind?



:( too drunk, and saw Borat... I'll try in the morning...
 
Originally posted by cultclassic@Nov 27 2006, 02:24 AM
differentiate the equation once to get velocity

KE = 0.5 x MASS x (velocity)^2
Would you leave it as (2.0 + 12.0t^2)^2 or keep going?
 
Originally posted by cultclassic@Nov 27 2006, 02:40 AM
:( too drunk, and saw Borat... I'll try in the morning...
Aww, go nap-nap. :) Thank you :wub: :wub: I got farther in the past 10 minutes then I did on my own with the other problems. :ph34r:
 
Originally posted by leone+Nov 27 2006, 03:55 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (leone @ Nov 27 2006, 03:55 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-cultclassic@Nov 27 2006, 02:24 AM
differentiate the equation once to get velocity

KE = 0.5 x MASS x (velocity)^2
Would you leave it as (2.0 + 12.0t^2)^2 or keep going? [/b][/quote]
you might wanna expand it...
 
I don't remember what the unit is but does 7848 sound like a reasonable kinetic frictional force of a car?


And to think, if.... when I fail this class, I'll have another year of this fun stuff. :ph34r:
 
No :ph34r: but I lucked out, it's due Wednesday. :woo:
 
Originally posted by leone@Nov 27 2006, 10:48 PM
No :ph34r: but I lucked out, it's due Wednesday. :woo:
Oh good!... Fitz sent some secret agents to your professors house... :ph34r:
 
:lol: Thank you Dingus! :wub:

Seriously dodged a bullet with this deadline. :ph34r:
 
Originally posted by cultclassic+Nov 27 2006, 09:05 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (cultclassic @ Nov 27 2006, 09:05 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-leone@Nov 27 2006, 10:48 PM
No :ph34r: but I lucked out, it's due Wednesday. :woo:
Oh good!... Fitz sent some secret agents to your professors house... :ph34r: [/b][/quote]
:lol: :lol: I missed this one. I don't know any secret agents. Just a bunch of military people with access to speedy transportation. :p
 
:lol: . o O (a humvee getting stuck betwixt the buildings)
 
:lol: . o O (A speedy fly-y thing getting its wings clipped on a building)
 
:lol: :lol: You want me to crash and burn sunthin awful huh. :p Hubby piss you of or sunthin? Hating men right now?Here.
 
:lol: :lol: I'ma call him Lava Lamp from now on and see how long it takes him to ask why.
 
:lol: :lol: :lol: @ you guys

I saw a similar list before. Remember these...
....chocolate
they go straight for the hips

....floor tiles
lay 'em right the first time and you can walk all over 'em for years.

:lol:
 
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