Question

By how many newtons does the weight of a 100-kg person change when he goes from sea level to an altitude of 5.0 km if we neglect the earth's rotational effects? (The mean radius of the Earth is 6.38

Answer 1

Acccelaraion due to gravity at the sea level is g = 9.8 m/s^2

accelaration due to gravity at altide h is gh = g(re/(re+h))^2

here g is the acclearation due to gravity at the sea level = 9.8 m/s^2

re is the Earth's mean radius

h is the height from the sea level = 6.38*10^6 m = 6380 km

gh= 9.8*[(6380)/(6380 + 5)]^2

gh = 9.785 m/s^2

Weight of the person at the sea level W1= 100*9.8 = 980 N

Weight of the person at an altitude 5km is W2 = 100*9.785 = 978.5 N

change in weight is W2-W1 = 978.5-980 = -1.5 N
so the answer is A) -1.5 N