Physics - Study Mode

[#301] A bullet is fired from a rifle which recoils after firing. The ratio of kinetic energy of the rifle to that of the bullet is
Correct Answer

(A) Zero

Explanation

Solution: Since, the the mass of the bullet is smaller than the mass of the rifle hence, the velocity of the bullet is more than the rifle recoil velocity. Also, kinetic energy is inversely proportional to the mass. Hence, when a bullet is fired from a rifle and the rifle recoils freely then the kinetic energy of the rifle will be less than that of bullet.

[#302] The height of a geo-stationary satellite from the Earth's surface is approximately :
Correct Answer

(A) 36,000 km

Explanation

Solution: The height of a geo-stationary satellite from the Earth's surface is approximately 36,000 km.

[#303] Why is weightlessness experienced while orbiting the earth in space ships ?
Correct Answer

(D) None of these

Explanation

Solution: Earth-orbiting astronauts are weightless for the same reasons that riders of a free-falling amusement park ride or a free-falling elevator are weightless. They are weightless because there is no external contact force pushing or pulling upon their body.

[#304] In the case of bodies falling under gravity which of the following remains constant at a given place?
Correct Answer

(C) Acceleration

Explanation

Solution: In the case of bodies falling under gravity acceleration remains constant at a given place.

[#305] The instrument used to see the distant objects on the Earth is
Correct Answer

(A) Terrestrial telescope

Explanation

Solution: The instrument used to see the distant objects on the Earth is Terrestrial telescope.