An object starts from rest and falls freely for
40. meters near the surface of planet P. If the
time of fall is 4.0 seconds, what is the magnitude
of the acceleration due to gravity on planet P?
(1) 0 m/s2 (3) 5.0 m/s2
(2) 1.3 m/s2 (4) 10. m/s2
please explain the reasoning behind this question. the answer is 3.