Today in physics we had project work time. Earlier in the week I mentioned writing instructions for how to find the upward force of a weather balloon. Here they are.
First find the radius of the balloon in meters, next use the radius to find the volume of the sphere. The equation is 4/3πr^2.
Next find out how much helium is in the balloon. Use the mass of He = He's density times volume formula. The density of He is 0.1664 kg/m cubed.
Then find out the mass of air displaced. Use the same formula as above, but replace the value of He's density with the density of air, 1.225 kg/m cubed.
Now, add up all of the downward forces, but be sure they are all in kg to stay consistent. Remember He's mass counts as a downward force.
To find the upward force, subtract the downward forces from the mass of air displaced. This number is your upward force, to convert it to Newtons, multiply it by Earth's Gravity, 9.81 m/s square.
To find the acceleration, use the upward force, in Newtons for F, and the downward force for m, in the F=ma equation. Solve for a algebraically.
This is how to do the problem set. It is due Monday along with the rest of your physics blog.