An alien on planet X walks towards a cliff. Starting from rest on a cliff, the alien jumps off it with a speed of 20 m/s and smash its head on the jagged rocks at
the bottom of the cliff in 4 seconds. Find
a. the acceleration due to gravity on that planet X,
b. the average speed during the 4 s,
c. the height of the cliff.​

Asample of a gaseous substance changes into a liquid

When you turn on a battery-operated device, an electrical circuit is

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s