A stone , when thrown on a glass window smashes the window pane to pieces , but a bullet from the gun passes through making a clean hole . Way ?
Answer
This is because velocity of bullet from the gun is very large . It takes very little time to cross the windown pane . Particles of window pane near the hole have to little time to share the motion of the bullet . Reverse is the case when stone is thrown with hand .
A heavy box of mass 20 kg is placed on a horizontal surface . If coefficient of kinetic friction between the box and the horizontal surface . Is 0.25 calculate the force of kinetic friction Also calculate acceleration produced under a force of 98 N applied horizontally ?
Calculate the power of an engine , which can just pull a train of mass 5000 quintals up an incline of 1 in 50 at the rate of \({54}{k}{m}/{h}\) . The resistance due to friction is\({0.8}{N}/\text{quintal}\). Take \({g}={9.8}{m}/{s}^{{{2}}}\) .
A vehicles of mass 10 quintals climba up a hill 200m high and thenmoves on a level road with a velocity of \({36}{k}{m}/{h}\) .Calculate its total mechanical energy while running on the top of the hill.
A very small particle rests on the top of a hemisphere of radius \({20}{c}{m}\). Calculate the smallest horizontal velocity to be given to it if it is to leave the hemisphere without sliding down its surface, take \({g}={9.8}{m}/{s}^{{{2}}}\).
A cylinder of radius \({R}\) and mass \({M}\) rolls without slipping down a plane inclined at an angle \(\theta\). Coeff. of friction between the cylinder and the plane is \(\mu\). For what maximum inclination \(\theta\), the cylinder rolls without slipping ? (A) \({{\tan}^{{-{1}}}\mu}\) (B) \({{\tan}^{{-{1}}}{\left({3}\mu\right)}}\) (C) \({{\tan}^{{-{1}}}{2}}\mu\) (D) \({{\tan}^{{-{1}}}.}\frac{{{3}}}{{{2}}}\mu\)
What volume of \({3}\) molar \({H}{N}{O}_{{{3}}}\) is needed to oxidise \({8}{g}\) of \({F}{e}^{{{3}+}}\), \({H}{N}{O}_{{{3}}}\) gets converted to \({N}{O}\) ? (A) \({8}{m}{L}\) (B) \({16}{m}{L}\) (C) \({32}{m}{L}\) (D) \({64}{m}{L}\)
One mole of \({N}_{{{2}}}{H}_{{{4}}}\) loses ten moles of electrons to form a new compound \({A}\). Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in \({A}\)? (There is no change in the oxidation state of hydrogen.)