Suppose a rock is dropped off a cliff with an initial speed of 0 ms. What is the rocks speed after 5 seconds in ms if it encounters no air resistance?

The rock would have a speed of 49 m/s after 5 seconds of free fall due to gravity (assuming g = 9.81 m/s^2). This is because its speed increases by 9.81 m/s every second during free fall.