calculate the horizontal force that must be applied to a 1-kg car to make it accelerate on a horizontal friction -free air table with the same acceleration it would have if it were dropped and fell freely.

Question

anonymous · Answer

i think it should be 9.8N

anonymous · Answer

yes it could be but i was wondering that does it matter thattjhe car is on  a friction-free table or is it like it's moving on a normal solid?

anonymous · Answer

if it is on a normal solid, then there will be a frictional force acting in backward direction. Hence it would be less than 9.8N

anonymous · Answer

frictional force is the same as contact force right?

anonymous · Answer

frictional force is due to attraction between particles or you can say molecules of the two bodies

anonymous · Answer

so whats the difference between them?

anonymous · Answer

i think it should be resultant of normal force and frictional force acting at the body.

anonymous · Answer

so if we saidfor example: a horizantal force of 100n is required to push a box across a factory floor at a constant speed. what is the net force acting on the box? 
 
and what is the frictional force here?

anonymous · Answer

frictional force is given as$$\mu r$$ here r is normal force acting on a body and $$\mu$$ is constant for a body

anonymous · Answer

and also r is equal to mg

anonymous · Answer

I would define friction more as the interaction of surfaces rather than the attraction. Gravity is an attractive force, friction is a resistive force, much the same as moving through a fluid or viscous medium provides a resistive force.