Recent content by mogley76

t = -rc* ln(1-vc/vn) got it thanks

Homework Statement C= 0.047 micro farads R= 2.2K using the formula given, calcultae the time taken to charge the capacitor to 2/3 V in. Homework Equations Vc = Vin * (1-e^-t/rc) The Attempt at a Solution rc= 2.2E3 * 0.047 E-6 = 1.034E-4 seconds ( 1 time constant , 63% of vin )...

Homework Statement calculate the critical angle for light at a water (n=1.33) and air (n=1) interface. if a fish is 2m below the surface of the water , calculate the area at the surface through which the fish can viw the world above the water. Homework Equations none given The...

Homework Statement when the switch is closed , describe what will happen to the meter reading, the direction of the current flow, if any, and the magnetic fields produced in the two coils Homework Equations none The Attempt at a Solution the current flow is shown in the pic...

sin crit angle =n2 right?

Homework Statement a ray of light traveling through glass is incident at the interface with air at an angle of 30 deg to the normal. if the ray is refracted at the critical angle, what is the refractive index of the glass? Homework Equations none The Attempt at a Solution sin...

Homework Statement A 5m long uniform plank of mass 8kg is supported by two pillars at 0.5m and 3m from the left hand end. a 20kg child walks along the plank towards the right hand end. calculate 1. the position the child ia at when the plank begins to tip 2. the forces exerted by the...

yay!:cool:

Homework Statement by using Newtons law of universal gravitaion and the relationship for the centripetal force, show that the orbital period T for a satellite circling a planet of mass M in orbit of radius r is given by : T= 2pi sqrt r^3/GM Homework Equations none given The...

Homework Statement give equations for angular momentum in terms of : 1. angular velocity 2. a point mass moving along the circumfrence of a circle with a tangential (linear) speed v. Homework Equations none The Attempt at a Solution 1. is L= I w...angular vel = moment of inertia X angular...

so...the recoil speed must be -1.4E7 m/s ? because thety both equal each other but in opposite directions?

m1v1=m2v2 but v1 is 0 right? so I am kinda puzzled as to how i can workout the recoil speed..

Homework Statement A Particle (x) of relative mass of 4 is emitted from a uranium 238 nucleus. Assuming the the particle (x) was originally at rest and was emitted with a speed of 1.4E7 m/s. calculate the recoil speed of the residual nucleus (thorium 234) Homework Equations none given The...

great! thanks!

so secondary wattage= Is * Vs : .06A*18Vrms which is 1.08 w and primary current = 1.08/primary vrms of 240 which is 4.5E-3 A?