Why must the bungee cord stretch relatively easily to avoid injuring the jumper? refer to linear momentum and impulse, and also work and kinetic energy. the jumper has a momentum (or energy) budget, but it is the high acceleration (force) that does damage. the question is tantamount to asking “how can we minimize the acceleration of the jumper? ”

Here we can say that if amount of acceleration is more than it will cause more damage

so here in order to decrease the acceleration we can say

so it is ratio of change in velocity and time interval

where if time interval is to be increased in order to decrease the amount of acceleration

So the time to stop after jumping from large height should be large so that acceleration will be very small.

In order to have large time we can say that the chord must have to stretch more amount so that it will take long time to stop and hence we will get less acceleration and this will cause least damage

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.