Posted by josh on .
a ball is thrown vertically upward from the ground with the velocity of 30m/s,
a)how long will it take to rise to its highest point?
b)how high does the ball rise?
c)how long after projection will the ball have the velocity of 10m/s upward?
tnx

physics 
drwls,
The variation of height (y, in meters) with time (t, in seconds) is given by the equation
y = 30 t  (g/2) t^2
g is the accelertaion of gravty, 9.8 m/s^2.
(a) The highest value of y is obtained when the velccity V is zero.
V(t) = dy/dt = 30  gt = 0
Solve for t.
(b) Use the value of t that you get in part (a) to solve for y(t) at that time.
(c) Set V(t) = +10 and solve for t.