Answer:
Final potential energy = 24 Joule
The velocity with which object must be thrown =
m/s
Step-by-step explanation:
<u>Given:</u>
Mass of object, m = 0.30 Kg
Height of object, h = 8 m
Acceleration due to gravity, g = 10 ![ms^{-2}](https://tex.z-dn.net/?f=ms%5E%7B-2%7D)
a) Formula for Potential Energy:
![E_p =mgh](https://tex.z-dn.net/?f=E_p%20%3Dmgh)
Where m is the mass of object
g is acceleration due to gravity and
h is the height of object
Putting the values of m, g and h
![E_p = 0.3 \times 10 \times 8\\\Rightarrow E_p =24 J](https://tex.z-dn.net/?f=E_p%20%3D%200.3%20%5Ctimes%2010%20%5Ctimes%208%5C%5C%5CRightarrow%20E_p%20%3D24%20J)
b) Formula for initial and final velocity:
![v^{2} =u^{2} +2gh](https://tex.z-dn.net/?f=v%5E%7B2%7D%20%20%20%3Du%5E%7B2%7D%20%2B2gh)
where v is the final velocity
u is the initial velocity with which the object is thrown
g is acceleration due to gravity and
h is the height obtained by object
here v = 0 at the height 8 m because it will come to rest at the point it attains the maximum height.
h = 8m
g = -10
(negative because the object's velocity is decreasing)
Putting the values to find 'u':
![0^{2} =u^{2} +2 \times -10 \times 8\\\Rightarrow u^{2} = 160\\\Rightarrow u = 4 \sqrt{10}\ m/s](https://tex.z-dn.net/?f=0%5E%7B2%7D%20%20%20%3Du%5E%7B2%7D%20%2B2%20%5Ctimes%20-10%20%5Ctimes%208%5C%5C%5CRightarrow%20u%5E%7B2%7D%20%3D%20160%5C%5C%5CRightarrow%20u%20%3D%204%20%5Csqrt%7B10%7D%5C%20m%2Fs)