A) 50 m
B) 25 m
C) 12.5 m
D) 10 m.
Correct Answer: C
Solution :
We know, if a body is thrown up vertically its KE goes on decreasing and PE goes on increasing. There is conversion of KE into PE. When kinetic energy becomes half of original value, the other half is converted into potential energy. Therefore, \[\frac{\text{490}}{\text{2}}\text{=2 }\!\!\times\!\!\text{ 9}\text{.8 }\!\!\times\!\!\text{ h}\] Or \[\text{h=}\frac{490}{2\times 2\times 9.8}\] or \[h=12.5m\] Thus, the required height is \[12.5m\]You need to login to perform this action.
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