Answer:
T = 2.79 sec.
s = 2.16 m
Step-by-step explanation:
from free fall formula we have following relation
S = VoT + (1/2)gT^2
where
S = distance from ground which is given 20 meters
Vo = initial velocity = -6.5 m/sec
T = time for bag to hit the ground
putting all appropriate values,
20 = -(6.5T) + (1/2)(9.8)T^2
solving for T
4.9T^2 - 6.5T - 20 = 0
T = 2.79 sec.
B)
V_f^2 - V_o^2 = 2gs
where
V_f = final velocity = 0
V_o = -6.5 m/sec
g =9.8 m/sec^2
s = height of bag before it strart to hit the ground
putting values,
0 - (-6.5)^2 = 2(9.8)s
42.25 = 19.6(s)
solving for "s",
s = 42.25/(2 * 9.8)
s = 2.16 m
.