An object has undergone acceleration if ...
-- it's moving faster than it was before
or
-- it's moving slower than it was before
or
-- it's moving in a different direction that it was before.
Time taken by the bowling ball to reach its highest point= 0.214 s
initial velocity= Vi=2.1 m/s
Final velocity= Vf=0 as the velocity at the highest point is zero.
acceleration= g= -9.8 m/s²
using the kinematic equation Vf= Vi + at
0= 2.1 + (-9.8)t
t= -2.1/-9.8
t=0.214 s
Thus the time taken by the bowling ball to reach its highest point is 0.214 s
Explanation:
It is given that,
Velocity in East, 
Velocity in North, 
(a) The resultant velocity is given by :

(b) The width of the river is, d = 80 m
Let t is the time taken by the boat to travel shore to shore. So,


t = 16 seconds
(c) Let x is the distance covered by the boat to reach the opposite shore. So,


x = 48 meters
Hence, this is the required solution.
Explanation:
a) 
where
is the distance of the mass
from the axis of rotation. When the axis of rotation is placed at the end of the rod, the moment of inertia is due only to one mass. Therefore,

b) When the axis of rotation is placed on the center of the rod, the moment is due to both masses and the radius r is 1.5 m. Therefore,

Carbon-14 has a relatively small half life of 5,730 years