Recent content by MattWakes

hey everyone, this is a qualitative question on gravitational orbits: I was going through questions in which the trajectory of the orbiting body is determined based upon the eccentricity of the orbit, e.g. 0<Ecc<1, ellipses, Ecc=1, parabola, Ecc>1, hyperbola. I did the math and found out what...

Yeah I guess there are variations to the equation out there. Would the constants not also divide out in the equation that you have mentioned, though?

The mass-radius relationship for a white dwarf star is defined by : R= (9pi)^0.66 /8 * h^2/m1 * 1/(Gm2^1.66*M^.333), where m1= electron mass, m2=proton mass, G=grav. constant, h=planck's constant I want to take a proportion with the solar mass and solar radius, which would involve a division...

Okay so I took the time derivative of d(y) and let it equal zero. Then after some algebra I obtained a quadratic expression, 2cos^2a-3cosa-1=0, which corresponds to the roots a=pi/3 and a=0. Of these, the second does not make sense. So in conclusion, if the math is right, the angle at which the...

gneill: I can give that a shot. I think the way I set it up could be the cause of the lack of real solutions. BvU: I think you're on the money. I'm seeing what I can get now if I apply that.

gneill: good point, I suppose as long as you are consistent the zero can be placed anywhere. Actually, I got the same velocity wherever the zero was placed. here is some of the math: min speed at top so string is not slack: (using a for angle) mv^2/r=mg+T, T=0, so v=root(rg) b is an arbitrary...

Homework Statement Use energy conservation to answer the following question. A mass is attached to one end of a massless string, the other end of which is attached to a fixed support. The mass swings around in a vertical circle as shown. Assuming that the mass has the minimum speed necessary at...

I got 42.9g. Can we think of the initial angle as 87 degrees and the final as 93, such that the sleigh rebounds from the wall perpendicularly? In that case, the direction of the impulse is 180

The flange and web are unknown to me. How do I calculate the cross sectional area of the beam?

Homework Statement A structural I-beam is made of steel. L = 12.1 cm, H = 32.0 cm and the width of the beam is W = 1.11 cm. What is the mass of a section 1.75 m long? The density of steel is 7.56E+3 kg/m3. Homework Equations d=m/v The Attempt at a Solution I can't copy the...

Hey, I figured it out. Using trig, tan(theta)=vy/vx=dy/dx. Dy=vydx/vx. Vit, if I substitute for t, is vydx/vx. Therefore, h of bullet= h-1/2gt^2, just as the height of the monkey. Thx for the help

Height h, the top of the branch, I expect. Then, vit converts to h and our quantities are equal. Yet how can I prove that mathematically?

The height for the monkey would be hm=h-.5gt^2 For the bullet, hb=vit-.5gt^2. I assume they're measured from the top of the tree branch? If the heights were the same, the question would be proven. However, how do I convert vit to height?

Thanks so much for the responses. They went a long way in demystifying this question. I now know that if the gun is pointed directly at the monkey, the force of gravity will act on both identically so that the bullet (I agree, should be arrow) and monkey will meet in midair. The quantities that...

Homework Statement A hunter on the ground aims his gun directly at a monkey hanging from a high tree branch some distance away. At the instant the gun is shot the monkey drops from the branch, hoping to avoid the bullet. Show analytically that the monkey made the wrong move. Ignore air...