Answer:
is the initial velocity of tossing the apple.
the apple should be tossed after

Step-by-step explanation:
Given:
- velocity of arrow in projectile,

- angle of projectile from the horizontal,

- distance of the point of tossing up of an apple,

Now the horizontal component of velocity:



The vertical component of the velocity:



Time taken by the projectile to travel the distance of 30 m:



Vertical position of the projectile at this time:



Now this height should be the maximum height of the tossed apple where its velocity becomes zero.


is the initial velocity of tossing the apple.
Time taken to reach this height:



We observe that
hence the time after the launch of the projectile after which the apple should be tossed is:


