Answer:
b. 20 sec
Explanation:
y = y₀ + v₀ t + ½ g t²
0 = 0 + (100) t + ½ (-10) t²
0 = 100t − 5t²
0 = t (100 − 5t)
t = 0, t = 20
The body lands after 20 seconds.
From the law of conservation of momentum
m1u1+ m2u2= m1v1+ m2v2
110*8+ 110*-10= 110*-10 + 110* v2
v2= 8 m/sec
-- The object either left or crossed the starting line exactly at time=0 .
-- The object has been traveling at constant speed for all time that
we know about.
