MCQ
In cold countries, water pipes sometimes burst, because
- APipe contracts
- ✓Water expands on freezing
- CWhen water freezes, pressure increases
- DWhen water freezes, it takes heat from pipes
Therefore water pipes sometimes burst, in cold countries.
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${y_1} = 8\,\cos\, \omega t;\,{y_2} = 4\,\cos \,\left( {\omega t + \frac{\pi }{2}} \right)$ ;
${y_3} = 2\cos \,\left( {\omega t + \pi } \right);\,{y_4} = \,\cos \,\left( {\omega t + \frac{{3\pi }}{2}} \right)$ ,
are superposed on each other. The resulting amplitude and phase are respectively;