NEET Test Series from KOTA - 10 Papers In MS WORD
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Gravitation
270639
A particle hanging from a spring stretches it by \(1 \mathrm{~cm}\) at earth's surface. Radius of earth is \(6400 \mathrm{~km}\). At a place \(800 \mathrm{~km}\) above the earth's surface, the same particle will stretch the spring by
1 \(0.79 \mathrm{~cm}\)
2 \(1.2 \mathrm{~cm}\)
3 \(4 \mathrm{~cm}\)
4 \(17 \mathrm{~cm}\)
Explanation:
\(e \propto g \quad\) Here, \(\quad \frac{g_{h}}{g}=\frac{R^{2}}{(R+h)^{2}}\)
Gravitation
270640
A tunnel is dug along a diameter of the earth. The force on a particle of mass ' \(m\) ' placed in the tunnel at a distance \(x\) from the centre is
1 \(\frac{G M_{e} m}{R^{3}} x\)
2 \(\frac{G M_{e} m}{R^{2}} x\)
3 \(\frac{G M_{e} m}{R^{3} x}\)
4 \(\frac{G M_{e} m R^{3}}{x}\)
Explanation:
\(F=\frac{G M^{\prime} m}{x^{2}}\) but \(\frac{M^{\prime}}{x^{3}}=\frac{M}{R^{3}}\)
270639
A particle hanging from a spring stretches it by \(1 \mathrm{~cm}\) at earth's surface. Radius of earth is \(6400 \mathrm{~km}\). At a place \(800 \mathrm{~km}\) above the earth's surface, the same particle will stretch the spring by
1 \(0.79 \mathrm{~cm}\)
2 \(1.2 \mathrm{~cm}\)
3 \(4 \mathrm{~cm}\)
4 \(17 \mathrm{~cm}\)
Explanation:
\(e \propto g \quad\) Here, \(\quad \frac{g_{h}}{g}=\frac{R^{2}}{(R+h)^{2}}\)
Gravitation
270640
A tunnel is dug along a diameter of the earth. The force on a particle of mass ' \(m\) ' placed in the tunnel at a distance \(x\) from the centre is
1 \(\frac{G M_{e} m}{R^{3}} x\)
2 \(\frac{G M_{e} m}{R^{2}} x\)
3 \(\frac{G M_{e} m}{R^{3} x}\)
4 \(\frac{G M_{e} m R^{3}}{x}\)
Explanation:
\(F=\frac{G M^{\prime} m}{x^{2}}\) but \(\frac{M^{\prime}}{x^{3}}=\frac{M}{R^{3}}\)