What term refers to the envelope of mixed gases confined close to a planet's surface by the force of gravity?

Which statement correctly describes a step-up transformer? a. it increases the amount of electric energy available. b. it increases the voltage of an electric current. c. it changes direct current into alternating current. d. it has more loops of wire in its primary coil.

Abatter hits a 0.140-kg baseball that was approaching him at 30 m/s and, as a result, the ball leaves the bat at 40 m/s in the reverse of its original direction. the ball remains in contact with the bat for 2.0 ms. what is the magnitude of the average force exerted by the bat on the ball?

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s