Answer:
Final speed of the ball, v = 20 m/s.
Step-by-step explanation:
It is given that,
Initial speed of the ball, u = 40 m/s
Time. t = 2 s
We need to find the speed of the ball after 2 seconds. Let it is denoted by v. It can be calculated using first equation of motion as :
![v=u+a* t](https://img.qammunity.org/2020/formulas/physics/high-school/6wgpu7lp42liwddwgyna8wgbl4jk0htxou.png)
Here, a = -g, as the ball is ball is moving under the action of gravity.
![v=u-g* t](https://img.qammunity.org/2020/formulas/physics/high-school/n1hkqaxhsi5v51e1ath1uoeu85qq7279g9.png)
![v=40-10* 2](https://img.qammunity.org/2020/formulas/physics/high-school/fybhig7yesxvry2tc5uja8n3yckwqez3jh.png)
v = 20 m/s
So, the speed of the ball after 2 seconds is 20 m/s. Hence, this is the required solution.