Some electronic devices operate on a DC voltage of 7.5 V. To obtain 7.5 V DC from a 120-V (rms) AC line, first the voltage is dropped to 7.5 V (rms) AC by a transformer, and then the 7.5 V AC is converted to 7.5 V DC by a rectifier circuit involving diodes. Consider a device of resistance 15 Ω connected to the 7.5-V DC output of the rectifier. Assuming no power loss anywhere, what is the rms current, in amperes, in the secondary winding? Again assuming no power loss anywhere, what is the rms current, in milliamperes, in the primary winding?

The charge on a charged sphere is: a)concentrated at its centerb)distributed uniformly throughout its volumec)clustered on its centerd)distributed uniformly over its surface

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?