help!!!

From: winlinux (i141802596_at_yahoo-dot-com.no-spam.invalid)
Date: 10/03/04 

Date: 3 Oct 2004 17:27:30 -0500

6. A rocket is fired vertically upwards from rest and burns fuel at a
constant rate k, and the exhaust gases are ejected vertically
downwards with constant speed u relative to the rocket. The initial
mass of the rocket is M', half of which is fuel. During the time that
the fuel is being burned, air resistance may be neglected and the
Earth’s gravitational field may be assumed to give rise to an
acceleration of constant magnitude g, where ku >M'g. Show that the
speed of the rocket when the fuel runs out is given by
uln2-gM'/2k, and find the distance traveled at this time.

2.According to Einstein’s theory of special relativity, the kinetic
energy K of a mass m moving at velocity v is given by

K=[(mc^2)/(1-(v/c)^2)^0.5]-mc^2

Show that at v<<c, the kinetic energy of the mass reduced to the
Newtonian expression.

5. (10 marks)
Two identical particles of mass m attract each other with a force that
obeys Newton’s third law. They are initially at rest on a smooth
inclined plane which has an angle of inclination of 45 degrees w.r.t.
the horizontal. Find the acceleration of the center of mass of the
system.

how to solve them?
thanks!

Relevant Pages

  • Re: Potentially painful-correction
    ... I gave the solution for constant acceleration and constant mass. ... messier for a rocket. ... mass of fuel at time t is mwhere m is the mass per second of the ... >> something to do with reference frames, and the velocity of the fuel ...
    (sci.electronics.basics)
  • Re: help!!!
    ... A rocket is fired vertically upwards from rest and burns fuel at a ... > downwards with constant speed u relative to the rocket. ... > mass of the rocket is M', half of which is fuel. ...
    (sci.physics)
  • Re: Konstantin Tsiolokvsky was wrong?!
    ... At half burn, ... Is mass changing over time, ... the total mass of the rocket decreases over time as the fuel is ...
    (sci.physics)
  • Re: Konstantin Tsiolokvsky was wrong?!
    ... At half burn, ... you've only used half the fuel. ... Is mass changing over time, ... the total mass of the rocket decreases over time as the fuel is ...
    (sci.physics)
  • Re: Further on "Rockets not carrying fuel."
    ... even those that have low energy to mass ratios, ... rocket fuel, or non-portable things tidal or geothermal stuff. ... > powerful as the shuttle main engines to send the gases up the pipe. ...
    (sci.astro)
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