while skydiving, a physics student launches himself horizontally out of an airpl
ID: 1703449 • Letter: W
Question
while skydiving, a physics student launches himself horizontally out of an airplane that is flying at 12,500 feet above the Earth at a speed of 80 mph. the total mass of the student and his gear is 110 kg. assume g=9.8m/s2. answer the following:
1) what is the magnitude of the gravitational force pulling on the student? A: 9.8m/s2 B: 980N C:1080N D:cant determined
3) after opening the chute, the student begin to fall with constant vertical speed, what is the force of air resistance acting on the student and his parachute? A: 0 N B: 980N C: 1080N D: 2160N
4) if there were no air and thus no wind resistance (vacuum) what will be the end result of student jump? A: the chute will still open, but he will hit the ground slightly faster B: there is no gravity in a vacuum, so he would not fall C:The chute would still open but he would float more slowly toward the ground
Explanation / Answer
1)The student experiences a free fall as he will be seeing his motion with respect to the airplane and so no horizontal velocity and only a free fall hence B.
2)The magnitude of force on the student will be 110 x 9.8 = 1078kg-m/sec2 [Force = mg]
3)The wind force is one forth of its weight hence air resistance = (1/4) x mg = 269.5 kg-m/sec2
Hence net force on the student = weight - air resistance = 1078 - 269.5 = 808.5 kg-m/sec2
Acceleration = 808.5/m = 808.5/110 = 7.35m/sec2
4)After the chute is opened there i no acceleration so weight - air resistance = 0
(or) air resistance = weight = mg = 1078kg-m/sec2
5)The student will continue falling with acceleration g downwards and constant velocity of 80mph horizontally and end up cashing the ground as a projectile in a parabolic path with respect to ground.
6)As the mass of the earth doubles the value of g doubles that is g becomes 9.8 x 2 = 19.6 so he starts with double the acceleration.
7) The best way to reduce his spinning speed is to stretch his hands and legs outwards from his body increasing his inertia and hence reduces his spinning speed. This is due to conservation of momentum.
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