A) \[70\text{ }km{{h}^{1}}\]
B) \[70.7\text{ }km{{h}^{1}}\]
C) \[65\text{ }km{{h}^{1}}\]
D) \[75\text{ }km{{h}^{1}}\]
Correct Answer: B
Solution :
[b] From, |
\[{{v}^{2}}{{u}^{2}}=2as\] |
\[\frac{{{80}^{2}}-\,{{60}^{2}}}{2a}\,=s\] |
\[s=\,\frac{6400\,-3600}{2a}\,\,=\,\frac{1400}{a}\] |
The middle point of the train is to cover a distance |
\[\frac{s}{2}=\,\frac{700}{a}\] |
From, \[{{v}^{2}}{{u}^{2}}=2as\] |
\[{{v}^{2}}-{{60}^{2}}=2a\times \,\frac{700}{a}\] |
= 1400 |
\[{{v}^{2}}=1400+3600\] |
\[v=\sqrt{5000}\] |
\[=70.7\text{ }km{{h}^{1}}\] |
You need to login to perform this action.
You will be redirected in
3 sec