1. mass of planet 1.23 x 10^24 kg radius 3.12 x 10^6 m

ligthest molecule that planet can keep hold of 2.34 x 10^-28 kg

What is the temperature in the upper edge of this planet's atmospehre. Answer in Kelvin K

2. Radius of earth 6 x 10^6m

mass 6x10^24kg

1AU = 1.5x10^11m

rotation period 23hrs 56min. Earth orbits the sun in exactly 365days.

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!

Calculate the capacitance of a system that stores 2.0 x 10^-10c of charge at 100.0 v. use c=q/v. a. 2.0 x 10^-12 f b. 2.0 x 10^-8 f c. 5.0 x 10^11 f d. 5.0 x 10^7 f