When removing the lug nut from a freeturning wheel using a w

When removing the lug nut from a free-turning wheel using a wrench, why is it best to keep the car tire on the ground rather than first jacking it up ?

Solution

When removing the lug nut from a free turning wheel using a wrench,it is best to keep the car tire on the ground because the frictional force between the tire and the road resist the tire to rotate while applying the torque on wrench.If the car is jacked up then while applying the torque tyre will be free to rotate and some resistive torque will be required to hold the tyre.