A company that makes playground equipment is designing a new swing. The swing will sit in an open schoolyard that is unprotected from the Sun.
The company wants to use a thermal insulator to make the swing. This is so that the swing will not get so hot from the Sun that it
burns the children when they touch it.
Which of the following materials are thermal insulators the company could use to make the swing?
1. wood
II. stainless steel
III. plastic
IV. rubber
OA. I, III, and IV only
ОВ. I and II only
OC. I, II, and Ill only
OD
II and IV only

In the image, the arrow is pointing to a celestial object. which attribute disqualifies the object from being a planet?

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!

Astone is dropped from a cliff and falls 9.44 meters. what is the speed of the stone when it reaches the ground? a. 13.6 m/sec b. 1.39 m/sec c. 185 m/sec d. 9.80 m/sec