Answer :
When the jumper jumps off , there is always a force of gravity acting on her which is 55*9.8 =539N downwards. (Considering the acceleration due to gravity to be 9.8)
Since the question says that the force exerted by cord is 825N upwards , it is obvious that the pseudo force of acceleration must act downwards and the jumper must be moving upwards.
Assume the acceleration at that instant be 'a' .
Pseudo force = mass * acceleration = 55*a
Since the body is in dynamic equilibrium , all forces must cancel out.
Hence ,
539 +55*a = 825
=> 55*a = 825-539 = 286
=> a = 286/55 = 5.2
So , acceleration at that instant was 5.2 m/s²
Since the question says that the force exerted by cord is 825N upwards , it is obvious that the pseudo force of acceleration must act downwards and the jumper must be moving upwards.
Assume the acceleration at that instant be 'a' .
Pseudo force = mass * acceleration = 55*a
Since the body is in dynamic equilibrium , all forces must cancel out.
Hence ,
539 +55*a = 825
=> 55*a = 825-539 = 286
=> a = 286/55 = 5.2
So , acceleration at that instant was 5.2 m/s²
Downward force = gorce of gravity (her weight)
= 55 x 9.8 = 539 newtons / / / Upward force = 825 newton. / / / Net force = 825 - 539 = 286 newtons upward. / / / F = m a / / / a = f / m = 286 / 55 = 5.2 meters per second squared Upward. / / / Note: We don't know the length of her fall before the bungee kicks in. At the moment we're dealing with, when her acceleration is 5.2 m/s-squared Upward, her velocity can very well be Downward.
