A rocket is fired upward from the earth's surface such that it creates an acceleration of $19.6 \,m/sec^2$. If after $5 \,sec$ its engine is switched off, the maximum height of the rocket from earth's surface would be.........$m$
A rocket is fired upward from the earth's surface such that it creates an acceleration of $19.6 \,m/sec^2$. If after $5 \,sec$ its engine is switched off, the maximum height of the rocket from earth's surface would be.........$m$
$245$
$490$
$980$
$735$
A rocket is fired upward from the earth's surface such that it creates an acceleration of $19.6 \,m/sec^2$. If after $5 \,sec$ its engine is switched off, the maximum height of the rocket from earth's surface would be.........$m$
Given $a = 19.6\;m/{s^2} = 2g$
Resultant velocity of the rocket after $5 \,sec$
$v = 2g \times 5 = 10g\;m/s$
Height achieved after 5 sec, ${h_1} = \frac{1}{2} \times 2g \times 25 = 245\,m$
On switching off the engine it goes up to height ${h_2}$ where its velocity becomes zero.
$0 = {(10g)^2} - 2g{h_2} \Rightarrow {h_2} = 490\,m$
$\therefore $Total height of rocket $ = 245 + 490 = 735\;m$
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