Let u be the velocity of the projection and O be the point of projection. Let P be the point in the path of the particle such that OP=h. Then,
$\displaystyle h=ut-\frac { 1 }{ 2 } { gt }^{ 2 }\Rightarrow { gt }^{ 2 }-2ut+2h=0$...(i)
Clearly, $\displaystyle { t } _{ 1 }{ t } _{ 2 }$, are two roots of this equation.
$\displaystyle \therefore \quad { t } _{ 1 }{ t } _{ 2 }=\frac { 2h }{ g } $
$\displaystyle \Rightarrow \quad h=\frac { 1 }{ 2 } g{ t } _{ 1 }{ t } _{ 2 }$

P.E of orbiting satellite at distance $r$ from centre of earth

$=\cfrac{-GMm}{r}\\K.E=\cfrac{GMm}{2R}$ and $M.E=\cfrac{-GMm}{2R}$

If $R$ decreased K.E increases.

P.E and M.E become more negative, thus decrease.

The wreckage will spin with no translatory motion$.$

The National Aeronautics and Space Administration (NASA) is an independent agency of the US federal govt. responsible for the civilian space program and aeronautics and aerospace research.

The given statement is true. Space shuttle carries satellites to space for research work. Along with research, space shuttle is also used to carry astronauts on various heavenly bodies for research work.

Temperature was bought down by about $10°C$ by rotating the spacecraft $20$degrees and switching of some of the instruments.

To receive and broadcast audio and video signals
Transponders basically receive and transfer signals in satellite communication. Hence, it can be used to broadcast received audio and video signals.

Remote Sensing is the process of acquiring Information about an object or phenomenon without making actual physical contact within, as opposed to onsite observation.

Jupiter is having largest no. of satellites.

While considering the motion of an object under the gravitational influence of another object, angular momentum and total mechanical energy are conserved.Linear momentum is not conserved

$\begin{array}{l} F=\dfrac { { G\left( M \right) m } }{ { { { \left( { 3R } \right)  }^{ 2 } } } }  \ \Rightarrow a=\dfrac { { GM } }{ { 9{ R^{ 2 } } } }  \ \therefore \dfrac { { { V^{ 2 } } } }{ { R' } } =a \ \Rightarrow \dfrac { { 2GM } }{ { 3R.R' } } =\dfrac { { GM } }{ { 9{ R^{ 2 } } } }  \ \Rightarrow R'=6R \ Hence, \ option\, \, A\, \, is\, \, correct\, \, answer. \end{array}$

Moon is called as earth satellite. The moon is called as earth satellite because moon moves around the earth. Earth and moon are called as natural satellites.