Question

अभिनव का द्रव्यमान 80किलो है 1000मी से छलांग लगया आधा उचाई तक मुक्त रुप से गिरा फिर पैराशूट के करन मंडित होते हुए जमिन पर अन्तिम वेग 10कीमी/सैकेण्ड से पहुचा तो प्रतिरोधी बल द्वारा किया गया कार्य होगा।

Answer 1

The Work done by retarding force is 396000 joules.

Explanation :

During first 500 m of free fall of Abhinav

u = initial velocity = 0 m/sec

v = final velocity

a = g = 10 m/sec²

s = 500 meters

s = ut + at²/2

500 = 0 + 10*t²/2

t = √100 = 10 sec

v = u + at = 0 + 10x10 = 100 m/sec

For the second part of the journey, Abhinav felt retardation to reduce the speed,

s = 500 meters

u = 100

v = 10 m/sec

v² – u² = 2as

a = (10x10 – 100x100)/2x500 = (100 – 10000)/1000 = -9.9 m/sec²

The retardation is 9.9 m/sec².

Work done = Force * distance = Mass * Acceleration * Distance

=> W = 80 x 9.9 x 500 = 396000 joules

Hence the Work done by retarding force is 396000 joules.