Recent content by hm8

Still not quite getting it. I understand that the LHS is the number of ways of choosing 2k+1 objects from n -- that's straightforward enough. I think its the summation on the RHS that's confusing me. So for each step of the summation I'm choosing k things from two groups; k from a group that...

Homework Statement Homework Equations {a \choose b} = \frac{a!}{(a-b)!b!}The Attempt at a Solution So I tried doing a mathematical induction proof (Show that it is true for some number, then show that if you assume it's true for 'k', it implies 'k+1') I was able to get the initial step, to...

What about p?

Homework Statement Show that \int\int\int \sqrt{x^{2}+y^{2}+z^{2}} e^{-({x^{2}+y^{2}+z^{2}})} dxdydz = \pi/4 where the bounds of x, y, and z are 0 to infinity (The improper integral is defined as the limit of a triple integral over the piece of a solid sphere which lies in the first...

Any help, guys?

Ok, so I just remembered that because its not slipping, I can change \alpha to \frac{a}{r} so I get f_{friction}R = MR^{2}*\frac{a}{R} which cancels down to f_{friction} = Ma But when I plug that back into the other equation I just get F - ma = ma... where did I go wrong?

Homework Statement A lawn roller in the form of a thin-walled, hollow cylinder with mass M is pulled horizontally with a constant horizontal force F applied by a handle attached to the axle. a)If it rolls without slipping, find the acceleration. b)If it rolls without slipping, find the...

Homework Statement A 12 inch long string with a 0.5 mm diameter and is composed of a 10GPa modulus material is fixed at one end and loaded by a 100 g mass at its other end. What is the length of the string when it is under load? (Note that the length is necessarily greater than 12 inches.)...

Homework Statement A car is traveling at 51.0 mi/h on a horizontal highway. If the coefficient of static friction between road and tires on a rainy day is 0.100, what is the minimum distance in which the car will stop?Homework Equations \Sigma \vec{F} = m \vec{a}...

Okay, so the rope is inclined at and angle of 0.00826 degrees above the horizontal. So the components of the tension vector would just be Cos(0.008)T and Sin(0.008)T So, in the Y direction... F = ma -mg + Sin(0.008)T = 0 -14.7 N + Sin(0.008)T = 0 T= 14.7 N/Sin(0.008) ...is that right so...

Okay...so the downward component of the tension force is 14.7 N? Still not sure where to go from there...how do I use the length of the wire and the amount it sags? I guess I can figure out that the length of one half of this 'V' is 23.0007 m (square root of .192 + (46/2)2), but does that help me?

Gah, somehow forgot to put the question in. Sorry. How much tension does the bird produce in the wire? Ignore the weight of the wire.

Homework Statement The distance between two telephone poles is 46.0 m. When a 1.50 kg bird lands on the telephone wire midway between the poles, the wire sags 0.190 m. How much tension does the bird produce in the wire? Ignore the weight of the wire. Homework Equations F=maThe Attempt at a...

Ahh...for some reason I was forgetting to multiply by g for the friction of block to...I was just doing μ*m The new answer (2.212 m/s^2) works! Thanks!

That was a typo, sorry...using the 2kg block (block 3) gives me the answer 2.74 m/s^2. My teacher also looked at my work today and said it looked okay, so I think it may just be a problem with how he programmed the answer into the online homework. Unless you see anything else wrong with it?