we know that as we move from earth to moon, the value of spring constant "k" and mass "m" remains unchanged because they do not depend on the acceleration due to gravity.
Time period depends on spring constant inversely and directly on the mass.
From 50km/h to 0km/h in 0.5s we need next acceleration: First we convert km/h in m/s: 50km/h = 50*1000/3600=13.8888 m/s a = v/t = 13.88888/0.5 = 27.77777 m/s^2
