A child having a mass of 30.0 kg jumps downward onto a trampoline at a speed of 4.0 ms. If the average impulsive force of the trampoline is 800.0 N and it acts upon the child for 0.5 sec in a vertica
a) 5.00 ms²
b) 10.00 ms²
c) 20.00 ms²
d) 40.00 ms²