Answer:
The angle of the launch is 17.09 degrees.
Step-by-step explanation:
Given that,
The initial speed of a cannon is 100 m/s
It is launched at some angle and it lands after being in the air for 6 s.
We need to find the angle of the launch.
The time taken by the projectile to reach the ground is called the time of flight. It is given by the formula as follows :

Here,
= launch angle

Hence, the angle of the launch is 17.09 degrees.