Answer:
Step-by-step explanation:
The values of the position and velocity of the ball are missing in the text - found the table in internet, see attached picture.
We can solve this problem by using the following SUVAT equation:
v(t) = u +at
where
v(t) is the velocity of the rock at time t
u is the initial velocity
a is the acceleration of gravity on the planet
t is the time
At t = 0, u = 20 m/s.
After 1 second, t = 1 and v = 15 m/s. Substituting these values and solving for a, we find:
And the negative sign means the acceleration is downward.