V=at and a=F/m
140/.070 = 2000m/s^2
2000*.020 = 40m/s
The ball’s velocity increased by 40m/s.
Answer:
After 9 seconds the object reaches ground.
Step-by-step explanation:
We equation of motion given as h = -16t²+128t+144,
We need to find in how many seconds will the object hit the ground,
That is we need to find time when h = 0
0 = -16t²+128t+144
16t²-128t-144= 0

Negative time is not possible, hence after 9 seconds the object reaches ground.
K=0.5 mu×u
K=2200J no matter the direction