MCQ
Rocket engines lift a rocket from the earth surface because hot gas with high velocity
  • A
    Push against the earth
  • B
    Push against the air
  • React against the rocket and push it up
  • D
    Heat up the air which lifts the rocket

Answer

Correct option: C.
React against the rocket and push it up
(c) lt works on the principle of conservation of momentum.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A stone is hung in air from a wire which is stretched over a sonometer. The bridges of the sonometer are $L \mathrm{~cm}$ apart when the wire is in unison with a tuning fork of frequency $N$. When the stone is completely immersed in water, the length between the bridges is $I$ $\mathrm{cm}$ for re-establishing unison, the specific gravity of the material of the stone is
A block of mass $4 kg$ is suspended through two light spring balanc $A$ and $B$. Then $A$ and $B$ will read respectively

Image

Under which of the following conditions will a convex mirror of focal length $f$ produce an image that is erect, diminished and virtual
Two forces are such that the sum of their magnitudes is $18 N$ and their resultant is perpendicular to the smaller force and magnitude of resultant is $12 N$. Then the magnitudes of the forces are
The maximum illumination on a screen at a distance of $2 \mathrm{~m}$ from a lamp is $25$ lux. The value of total luminous flux emitted by the lamp is
If the amount of heat given to a system be $35$ joules and the amount of work done by the system be $-15$ joules, then the change in the internal energy of the system is
Energy required to move a body of mass $m$ from an orbit of radius $2 R$ to $3 R$ is
A body of mass $m$ rises to height $h=R / 5$ from the earth's surface, where $R$ is earth's radius. If $g$ is acceleration due to gravity at earth's surface, the increase in potential energy is
Radius of a soap bubble is increased from $R$ to $2 R$ work done in this process in terms of surface tension is
An electric motor exerts a force of $40 \mathrm{~N}$ on a cable and pulls it by a distance of $30 \mathrm{~m}$ in one minute. The power supplied by the motor (in Watts) is