Q. An 80 kg person is parachuting and is experiencing a downward acceleration of$\ 2.8{ms}^{- 2}$. The mass of the parachute is 5 kg. The upward force on the open parachute is (Take $g = 9.8{ms}^{- 2})$
A) 595 N
B) 675 N
C) 456 N
D) 925 N
Explanation
(a) Mass of the person $M = 80$ kg
Mass of the parachute $m = 5$ kg
$\therefore$ Total mass of the system $= M + m = 85$kg
Downward acceleration $a = 2.8\ {ms}^{- 2}$
Let upward force $= F$
Applying Newton’s II law of motion to this system
$F = (m + M)g - (m + M)a$
$or\ \ F = (m + M)(g - a)$
$F = 85(9.8 - 2.8)N$
$= 85 \times 7\ N$
$F = 595\ N$
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.