Answer:
Given :-
- A ball thrown vertically upward with a speed of 19.6 m/s from the top of the tower and returns to the earth in 6 seconds.
To Find :-
- What is the height of the tower.
Formula Used :-
Second Equation Of Motion Formula :
![\mapsto \sf\boxed{\bold{\pink{h =\: ut + \dfrac{1}{2}gt^2}}} \mapsto \sf\boxed{\bold{\pink{h =\: ut + \dfrac{1}{2}gt^2}}}](https://tex.z-dn.net/?f=%5Cmapsto%20%5Csf%5Cboxed%7B%5Cbold%7B%5Cpink%7Bh%20%3D%5C%3A%20ut%20%2B%20%5Cdfrac%7B1%7D%7B2%7Dgt%5E2%7D%7D%7D)
where,
- h = Height
- u = Initial Velocity
- t = Time Taken
- g = Acceleration due to gravity
Solution :-
Given :
- Initial Velocity (u) = 19.6 m/s
- Time Taken (t) = 6 seconds
- Acceleration due to gravity (g) = - 9.8 m/s²
According to the question by using the formula we get,
![\longrightarrow \sf h =\: (19.6)(6) + \dfrac{1}{2} \times (- 9.8)(6)^2 \longrightarrow \sf h =\: (19.6)(6) + \dfrac{1}{2} \times (- 9.8)(6)^2](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20%2819.6%29%286%29%20%2B%20%5Cdfrac%7B1%7D%7B2%7D%20%5Ctimes%20%28-%209.8%29%286%29%5E2)
![\longrightarrow \sf h =\: 19.6 \times 6 + \dfrac{1}{2} \times - 9.8 \times 6 \times 6 \longrightarrow \sf h =\: 19.6 \times 6 + \dfrac{1}{2} \times - 9.8 \times 6 \times 6](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%2019.6%20%5Ctimes%206%20%2B%20%5Cdfrac%7B1%7D%7B2%7D%20%5Ctimes%20-%209.8%20%5Ctimes%206%20%5Ctimes%206)
![\longrightarrow \sf h =\: 117.6 + \dfrac{1}{2} \times - 58.8 \times 6 \longrightarrow \sf h =\: 117.6 + \dfrac{1}{2} \times - 58.8 \times 6](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20117.6%20%2B%20%5Cdfrac%7B1%7D%7B2%7D%20%5Ctimes%20-%2058.8%20%5Ctimes%206)
![\longrightarrow \sf h =\: 117.6 + \dfrac{1}{2} \times - 352.8 \longrightarrow \sf h =\: 117.6 + \dfrac{1}{2} \times - 352.8](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20117.6%20%2B%20%5Cdfrac%7B1%7D%7B2%7D%20%5Ctimes%20-%20352.8)
![\longrightarrow \sf h =\: 117.6 + ( - 176.4) \longrightarrow \sf h =\: 117.6 + ( - 176.4)](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20117.6%20%2B%20%28%20-%20176.4%29)
![\longrightarrow \sf h =\: 117.6 - 176.4 \longrightarrow \sf h =\: 117.6 - 176.4](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20117.6%20-%20176.4)
![\longrightarrow \sf h =\: - 58.8\: \: \bigg\lgroup \small\sf\bold{\pink{Height\: can't\: be\: negative\: (-\: ve)}}\bigg\rgroup\\ ></p><p><img src=](https://tex.z-dn.net/?f=%5Clongrightarrow%20%5Csf%20h%20%3D%5C%3A%20-%2058.8%5C%3A%20%5C%3A%20%5Cbigg%5Clgroup%20%5Csmall%5Csf%5Cbold%7B%5Cpink%7BHeight%5C%3A%20can%27t%5C%3A%20be%5C%3A%20negative%5C%3A%20%28-%5C%3A%20ve%29%7D%7D%5Cbigg%5Crgroup%5C%5C)
![{\small{\bold{\underline{\therefore\: The\: height\: of\: the\: tower\: is\: 58.8\: m\: .}}}} {\small{\bold{\underline{\therefore\: The\: height\: of\: the\: tower\: is\: 58.8\: m\: .}}}}](https://tex.z-dn.net/?f=%7B%5Csmall%7B%5Cbold%7B%5Cunderline%7B%5Ctherefore%5C%3A%20The%5C%3A%20height%5C%3A%20of%5C%3A%20the%5C%3A%20tower%5C%3A%20is%5C%3A%2058.8%5C%3A%20m%5C%3A%20.%7D%7D%7D%7D)
Answers & Comments
Verified answer
Answer:
58.8 metres is the required height of the tower .
Explanation:
According to the Question
It is given that ball thrown vertically upward with a a speed of 19.6 m/s from the top of the tower and returns to the earth in 6 second. we need to calculate the height of the tower . obviously the height of tower is equal to the day distance covered by the ball in given time interval.
So , using Kinematics Equation
Acceleration due to gravty is 9.8m/s²
where,
h denote height of tower
u denote initial velocity
t denote time taken
g denote acceleration due to gravity
substitute the value we get
➻ h = 19.6×6 + ½×(-9.8) × 6² {as accⁿ due to gravity is acting in. downward direction)
➻ h = 117.6+ ½ × (-9.8)×36
➻ h = 117.6+ (-9.8)×18
➻ h = 117.6 - (9.8×18)
➻ h = 117.8 - 176.4
➻ h = -58.8m
➻h = 58.8 (as height cannot negative and its show that the ball covered 58.8 m distance from the top of the tower).