Aball is thrown vertically upward, which is the positive direction. a little later it returns to its point of release. the ball is in the air for a total time of 8.14 s. what is its initial velocity? neglect air resistance.

This motion of all can be divided in to two, first the upward motion and second downward motion.

In case of projectiles time taken for upward motion = time taken for downward motion.

So we have time taken for upward motion = 8.14/2 = 4.07 seconds

We have equation of motion, v = u+at, where v is the final velocity , u is the initial velocity, a is the acceleration and t is the time taken.

In case of upward motion

    v = 0 m/s

    t = 4.07 seconds

    a = -9.8

  Substituting

So initial velocity of ball = 39.886 m/s.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)