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Your answer : The bowlers and fielders rub the ball to make the ball smooth and shiny on one side and leave it rough on the other side. To generate reverse swing. There is a lot of science behind swinging the ball. The ball gets reverse swing when it is quite old and you see not only the bowlers but the fielders as well rubbing the ball before every ...


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but perhaps, given sufficient throwing speed If you throw your egg too fast, the force due air resistance $$F = \frac{cW\cdot A\cdot \rho\cdot v^2}{2}$$ will exceed the 50 Newton you mentioned before and the egg will break. and, or, car speed, perhaps it is possible If the car speed is fast enough the glass will of course break, since even ...


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Assuming the interpretation I suggested in the comments is correct. Consider the normal support force. It is an expression of the solidity of the surface that won't allow interpenetration. In order for penetration to not happen, there must be a force to prevent the supported object from accelerating toward the surface. Ultimately the origin of this ...


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Even I didn't get you but I may help you how much I can by describing your case. Your case have two bodies which are being rubbed against each other in opposite direction with constant acceleration. The definition of friction is, "The resistance which either one of the bodies offers to this motion is called the force of friction and is said to be due to ...


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Philosopher who said to you that the pressing force taken for friction's calculation is Normal force or reaction force exerted by earth on body? Actually, the pressing force is called the normal force (not reaction force) Since it is the force perpendicular or "normal" to the surfaces which affects the frictional resistance, this force is typically called ...


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No. Lying down on a surface could only serve to change the coefficient of friction, but the problem asks you to suppose that it's zero. The general proof that you absolutely cannot do it by any motion, is the fact that with only gravity as an external force, momentum is conserved in the horizontal directions. The force of gravity and the normal force of ...


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When we hit a friction-less surface with a hammer, we have to bring the hammer towards the surface with a velocity. Now it is given that we are bringing the hammer at a non-perpendicular plane. Therefore the velocity will have two components : perpendicular to the surface and parallel to the surface. The velocity parallel to the surface will remain ...


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The direction of kinetic friction is in the opposite direction of the velocity of the box and independent from acceleration thus whether the $\mathbf a$ is positive, negative or zero does not affect the direction of the friction vector



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