A two part calculation dealing with the required volume of helium to lift a balloon.

A. A helium filled balloon is to lift a load of 2000 kg. The mass of the empty balloon itself is 150 kg. Calculate the minimum volume of helium needed to fill the balloon to produce the required lift. P air=1.28kg/m^3 P He=0.179kg/m^3 B. If the volume of the balloon is made 20% larger than that required in part A, what will be the initial upward acceleration of the balloon when it is released? Assume the mass of the empty balloon itself increases proportionally with area and that the balloon always has a spherical shape.

multiple choice

1) Which of the following equations describes an oscillating system moving through its equilibrium, position at t=0? a.x=A cos (wt) b.x=A sin (wt) c.x=wAcos(wt) d.x=w^2Asin(wt) 2)Fluid moving through a pipe may experience changes in certain physical parameters. Which of the following will not change under any circumstances? a.pressure b.volume flow rate c.speed d.potential energy 3)which of the following does not represent simple harmonic osillation? a.a log bobbing up and down in water b.a hanging wooden sign making small back and forth swings c.a communication satellite in a circular orbit d.a car on old springs 4)If you could double the inertia of an object being ac... click for more

short questions

1)how do you convert gauge pressure to absolute pressure? 2)What is Bernoulli's principle regarding pressure and fluid speed? 3)The moment arm used to calculate the magnitude of torque is defined as? 4.young's modulus is the ratio of? 5.An object will float in liquid if: a.its full volume displaces more liquid than it weights b.its full volume displaces less liquid than it weights c.its full volume displaces exactly its weight of liquid d.all of the above 6)as fluid passes through a consriction the speed of the fluid increases. by doing so: a.the kinetic energy per unit volume of the fluid remains constant b.the pressure in the fluid remains constant c.the mass flow rate in the f... click for more

Determining the minimum escape velocity required to get a rocket out of an orbit.

A rocket is in an elliptic orbit around the earth. To put it into an escape orbit, its engine is fired briefly, changing the rocket's velocity by (delta) V. Where in the orbit, and in what direction, should the firing occur to attain an escape with a minimum value of (delta) V?

Calculating how high a projectile fired from Earth's surface rises.

A projectile of mass m is fired from the surface of the earth at an angle A from the vertical. The initial speed Vo is equal to the square root (GMe/Re). How high does the projectile rise? Neglect air resistance and the earth's rotation. (Hint: It is probably easier to apply the conservation laws directly instead of using orbit equations.) If A=60 degrees then Rmax=3Re/2