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To move an object, which one is easier, push or pull? Explain |
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Answer» Solution :When a body is pushed at an arbitraryangle `theta(0 " to " (pi)/(2))`, the applied force F can be resolved into two components as F `SIN theta` PARALLEL to the surface and F `cos theta` perpendicularto the surface as shown in Figure. The total downward force ACTING on the body is `mg+Fcos theta`. It implies that the normal force acting on the body increases. Since thereis no acceleration along the verticaldirectionthe normal force N is equal to `N_("push")=mg+F cos theta""...(1)` As a result the maximal static friction also increases and is equal to `f_(s)^("max")=N_("push")=mu_(s)(mg+Fcos theta)""...(2)` Equation (2) shows that a greater force needs to be applied to push the OBJECT into motion.  When an object is pulled at an angle `theta`, the applied force is resolved into two components as shown in Figure. The total downward force acting on the object is `N_("pull")=mg+F cos theta"" ...(3)`  Equation (3) shows that the normal force is less than `N_("push")`. From equations (1) and (3), it is EASIER to pull an object than to push to make it move. |
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