Recent content by Shadowsol

[b]1. Compute the cost per hour at 8 cents per kw-hr of electrically heating a room if it requires 1 kg per hour of anthracite coal having a heat of combustion of 8000 kcal/kg. 2. The lights on a car are left on. They dissipate 95 watts. How long will it take for the fully charged 12-volt...

[b]1. Two pith balls each have a mass of 1 g. and equal charge. One pith ball is suspended by an insulating thread. The other is brought to 3 cm from the suspended ball. The suspended ball is now hanging with the thread forming an angle of 30 degrees with the vertical. The ball is in equlibrium...

[b]1. A .5 Kg block rests on a horizontal fricionless surface. The block is pressed back against a spring having a constant of K =625 Newtons per meter. The spring is compressed .1 meters. Then the block is released. Find the maximum distance the block travels up the frictionless incline if the...

Ok, so I put in the force*the distance it was pulled back to get the potential sling shot energy. I than set that equal to the KE equation and got V. Than I simply used that V as V0, used 9.8 as A, and 18 m as D, than solved for V1. Is this correct?

[b]1. An average force of 8.2 Newtons is used to pull a .4 kg rock, stretching a sling shot 43 centimeters. The rock is shot downward from a bridge 18 meters above a stream. What will be the velocity of the rock just before it hits the water? How much time will it take to hit the water...

I got 11.76 M/S when solving that, that seems a bit too fast...it this correct?

Ok, for kinematics to solve for V, is 50=((0+V)/2)*8.5 right? Does this give me his constant velocity over the 50m?

[b]1. A sprinter, whose mass is 75 kg, runs a 50 meter dash. The total elapsed time is 8.5 seconds. The sprinter accelerates at a constant rate over the first second and runs the rest of the race at constant velocity. a. Calculate the average power produced for the first second. b. What is...

Ok, for the first part, i got Fa= 3131 N. I did Fa-700-mgsin10=0, than solved. I don't know the d however, so I don't know how to solve for work, which is what I need. Also, is the 60% engine part extra information I don't need? For the final part do I combine the total work of both...

[b]1. I have this tough question on power and work. "Calculate the power required of a 1400 kg car under the following circumstances a) the car climbs a 10 degree hill at a constant velocity of 80km/hr. b) the car accelerates along a level road from 90 to 110 km/hr in 6 seconds. Assume in both...

Thank you so much for your help! :)

I keep getting va1-vb1=vb2-va2, I can't seem to get vb2 to be negative.

Is there a paranthesis on the right side?

Ok after trying it your way, it seems I may have copied the original equation wrong. Is it va1-vb1=-vb2-va2 as opposed to the one I first posted, where it is va1 on the right side instead of va2? The va1 on the left and right side doesn't seem to make sense, so I think I posted the wrong...

Ok, I got: ma(Va1squared-va2squared)=mb(vb2squared-vb1squared) I got all the ma and mb terms to their respective sides. Now do I combine that with the KE equation? Would the Ke equation be: .5ma1va1=.5mb1vb2 ? Since object A's intial velocity/momentum has Kinetic energy, but when...