A) \[{{30}^{o}}\]
B) \[{{45}^{o}}\]
C) \[{{60}^{o}}\]
D) \[{{120}^{o}}\]
Correct Answer: A
Solution :
The kinetic energy at the highest point would be equal to \[\frac{1}{2}m\,{{(u\,\cos \,\beta )}^{2}}\] as the vertical component of the velocity is zero. The initial kinetic energy is the maximum kinetic energy. So, \[KE=Kd{{\cos }^{2}}\beta \] Thus, \[K\,{{\cos }^{2}}\beta =\frac{3}{4}K\] \[\Rightarrow \] \[\cos \beta =\frac{\sqrt{3}}{2}\] \[\Rightarrow \] \[\beta ={{30}^{o}}\]You need to login to perform this action.
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