Force required to move a mass of 1 kg at rest on a horizontal rough plane ($$\mu$$ = 0.1 and g = 9.8 m/s2) is
A rocket of mass 100 kg burns 0.1 kg of fuel per sec. If the velocity of exhaust gas is 1 km/sec, then it lifts with an acceleration of
A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms$$-$$1. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is
The minimum force required to start pushing a body up a rough (having co-efficient of friction $\mu$ ) inclined plane is $\vec{F}_1$ while the minimum force needed to prevent it from sliding is $\overrightarrow{F_2}$. If the inclined plane makes an angle $\theta$ with the horizontal such that $\tan \theta=2 \mu$, then the ratio $F_1 / F_2$ is