Recent content by Runaway

ok, so 1/2 * 57grams * (35ft/s)^2 + 57grams*sqrt(1.75ft^2)/2*9.81m/s/s = 3.4562 joules so to release this amount of energy as the ball travels the 1.75ft barrel length, the avg. force applied will need to be 6.292 Newtons, and then the initial force would be 12.58 Newtons or 2.83lbs...

ok, using the quadratic you set up I set it as -1.237= Vy*t -16.1 t^2, and t=40ft/Vy, and I got Vy=25ft/s, Vf=sqrt(2*(25ft/s)^2)=35.35ft/s V^2=2a(1.75) V^2 /2.5 = a = 499.7ft/s^2 F=ma = 499.7ft/s^2 * 57g = 8.6816N = 1.95lbs Am I correct in assuming I should double this to find the initial...

Homework Statement Ok, for my Mechanical engineering class we have been assigned to make a 2ft ^3 5kg device that will launch a tennis ball 20-40 ft. My group decided to use a design more or less like a crossbow, so I was hoping someone would look over my calculations and make sure they're...

Homework Statement A proton is released from rest in a uniform electric field of mag. 90000 V/m directed along the positive x axis. the proton undergoes a displacement of .2m in the direction of the electric field. Find the change in electric potential. Homework Equations no idea...

I talked with the teacher and I was misreading the problem, it wants it to have the 9.49 E-8 F capacitance before it's rolled, not after, and the part about C being doubled when it is rolled was just put there to explain why there is a difference before and after it's rolled. Thanks for your help ;)

Ok, I tried: (9.49 * 10^-8 F/2 * .0246 mm)/(3.9 * 8.85 * 10^-12C^2 / (N * m^2) *7.43cm) Instead and got 0.4552 meters, but it still says the answer is incorrect

Homework Statement Homework Equations C = k *\epsilon0 * A / d The Attempt at a Solution I attempted setting the equation up as: C/2 (because rolling the capacitor doubles C) = k * \epsilon0 * L * W / d 9.49 * 10-8 F/2 = 3.9 * 8.85 * 10-12C2 / (N * m2) * L * 7.43cm / .00282 mm...

ok, so k = q/q0

C= k\epsilon0 A / d so k= C/ (\epsilon0 A / d) But I still don't have A or d, so how does that help me?

Homework Statement When a certain air-filled parallel-plate capacitor is connected cross a battery, it acquires a charge (on each plate) of 130 μC. While the battery connection is maintained, a dielectric slab is inserted into and fills the region between the plates. This results in the...

Thanks for all your help, I figured it out: 16.0m/s

I don't see how that helps me account for the fact that the acceleration isn't constant due to the forces increasing as the distance between them decreases.

Homework Statement Two insulating spheres having radii 0.22 cm and 0.42 cm, masses 0.16 kg and 0.47 kg, and charges −4 μC and 5 μC are released from rest when their centers are separated by 1 m. How fast is the smaller sphere moving when they collide? Answer in units of m/s...

Homework Statement A power plant has a power output of 1246 MW and operates with an efficiency of 34.8 percent. Excess energy is carried away as heat from the plant to a nearby river that has a flow rate of 1.4 * 10^6 kg/s. How much energy is transferred as heat to the river each second...

Thanks for bearing with me and helping me figure it out :)