1. baseball in air w/ no force but only gravity acting on it. gravity is constant so its acceleration is constant. ans is A.
2. use the eqn s=u*t+1/2a*t^2 where u=init vel n a=accel
s=105m,
u=0 as the rock has no vertical vel
n a=gravity=9.8m/s^2
105=0*t+1/2*9.8*t^2
t^2~23
t~5s
ans is A.
3. same eqn s=u*t+1/2a*t^2 where u=init vel n a=accel
s=1.4m,
u=0 as the marble has no vertical vel
n a=gravity=9.8m/s^2
1.4=0*t+1/2*9.8*t^2
t^2=2.8/9.8=0.2857
t=0.5345s
V=4/0.5345=7.48m/s
ans is C
