A) \[5\,\,m/s\]
B) \[15\,\,m/s\]
C) \[30\,\,m/s\]
D) \[7.5\,\,m/s\]
Correct Answer: A
Solution :
Key Idea: Average velocity\[=\frac{Displacement}{Time\,\,taken}\] Let body move along\[AB\], then\[BC\]. Distance travelled in\[2\,\,s\]. \[{{S}_{1}}=15\times 2=30\,\,m\] Distance travelled in\[8\,\,s\] \[{{S}_{2}}=5\times 8=40\,\,m\] \[\therefore \]Displacement\[AC=\sqrt{{{(30)}^{2}}+{{(40)}^{2}}}\] \[=\sqrt{900+1600}=\sqrt{2500}\]0 \[=50\,\,m\] Hence average velocity\[=\frac{displacement}{time\,\,taken}\] \[=\frac{50}{8+2}=5\,\,m/s\]You need to login to perform this action.
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