Recent content by xelda

Awesome. Thank you so much for your help!

Homework Statement An electron has a de Broglie wavelength of λ = 6.4e-10m. What is its speed? What voltage was needed to accelerate to this speed? Homework Equations v=h/mλ KE = 1/2mv^2 The Attempt at a Solution I already determined that the speed is 1.136e6 m/s. Finding the...

Thanks for your help! I can understand your explanations, but could you elaborate more on number 6? From what I've interpreted in the textbook, the total energy would be conserved due to the law of conservation of energy, isn't it?

1) A ball is thrown from a tall building at some angle with respect to the horizontal. By measuring the height of the building and the distance that the ball lands from the base of the buiding, one can uniquely determine the speed of the ball when it hits the ground. I put this down as false...

I would assume the normal force is mg x sin theta, but I was told this was incorrect?

I think you calculated velocity correctly but you left off the scientific notation. Keep the velocity squared and use that to solve for the acceleration. a = v^2 / r This will give you the answer in m/s^2

Whis is the minimum work needed to push a 1068 kg car 305 m up a 11.0 degree incline if the effective coefficient of friction is 0.26? I have a hard time understanding why the normal force does not equal mg? How do I find the normal force? Or am I looking at this problem incorrectly?

Wow, that easy, huh? Haha, thanks for your help!

Astronomers using the Hubble Space Telescope have recently deduced the presence of an extremely massive core in the distant galaxy M87, so dense that it could well be a black hole (from which no light escapes). They measured the speed of gas clouds orbiting the core to be 758 km/s at a distance...

How much would someone who has a mass 54.1 kg on Earth weigh if they were to stand on the surface of Mars? (Take RMars= 3393 km and MMars=6.45x10^23 kg. I've been using the formula F=GmM/R^2 with the 3393km converted to meters. (6.67 x 10^-11 Nm^2/kg^2) (54.1 kg) (6.45 x 10^23kg) /...

Thanks for the help! I got the right answer after reading all of your hints, but I'll have to think about it some more to make sense of it.

I'm still confused. :x

A force of 45.7 N is required to start a 5.0-kg box moving across a horizontal concrete floor. (a) What is the coefficient of static friction between the box and the floor? (b) If the force continues at the same value, the box accelerates at 0.54 m/s^2. What is the coefficient of kinetic...

Okay, I finally got it! Thanks for the help. :)

I've been given this problem: Two forces act on a block of mass 14.1 kg. The first force has magnitude 28.5 N and is directed along the x axis. The second force has magnitude 6.7 N and is directed at an angle of 38.7 degrees to the x axis. Find (a) the magnitude and (b) the direction (i.e., the...