Two 2.0 kg bodies, a and b, collide. the velocities before the collision are
v→a=(15i^+30j^) m/s
and
v→b=(−10i^+5.0j^) m/s
. after the collision,
v→a=(−5.0i^+20j^) m/s
. what are (a) the final velocity of b and (b) the change in the total kinetic energy (including sign)?

Aball is thrown from the top of a building with an initial velocity of 21.9 m/s straight upward, at an initial height of 51.6 m above the ground. the ball just misses the edge of the roof on its way down, as shown in the figure. (a) determine the time needed for the ball to reach its maximum height. (b) determine the maximum height. (c) determine the time needed for the ball to return to the height from which it was thrown, and the velocity of the ball at that instant. (d) determine the time needed for the ball to reach the ground. (e) determine the velocity and position of the ball at t = 5.35 s.

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?