Recent content by LD_90

Thanks guys. Sorry about not posting my method. I'll give more complete posts in the future and try to learn to LATEX. Well for the problem I assumed an isolated system and used the fact that the total momentum of an isolated system is constant. In this case p_{1} + p_{2}=0 Thanks again

I'm doing some problems from an old text that seems to be plagued with errors in the answer key. I think my method is correct, but if someone could confirm my answers to this problem, I'd very much appreciative. Two girls sit on opposite ends of a sled 6.0 m long initially at rest on...

Thanks for the help!

A 1.00 kg steel ball 4.00 m above the floor is released, falls, strikes the floor, and rises to a maximum height of 2.50 m. What is the momentum transferred from the ball to the floor in the collision? Ok the momentum down before the collision is around -8.85 kg m/s, up after the collision...

Thank you arildno. It all clicked after I read your first post.

The acceleration of a particle moving at constant speed is perpendicular to its instantaneous velocity. How can I show this by using the fact that d(v^2)/dt=d(v. v )/dt=0? This doesn't seem like the most direct way to look at the concept. Help me out.

Thanks for the help.

I've been working on this for awhile. I think I've got it. Ok here's the problem: A particle moves in a circle of radius r completing one cycle in time T. What is the magnitude of the average acceleration over time T and over time T/2? It seems to me that over time T the magitude of the...

Well I guess the answer in the book is wrong. Thanks for the help.

Thanks Doc Al. That's the answer that I got too. Since it did not match the back of the book answer, I took the difference in stopping times, (plus the delay) and multiplied it by the initial velocity. This gives about 30.8m. This gets a result closer to the book answer, but it doesn't seem...

I found this problem in the text "Elementary Physics Classical and Modern" by Weidner and Sells. Two automobiles are both moving at 90 km/h in the same direction, one directly behind the other. The driver of the lead car suddenly applies his brakes, decelerating at 7.5 m/s^2. The other...