A cart is set rolling across a level table , at the same speed on every trial. If it runs into a patch of sand, the cart exerts on the sand an average horizontal force of `6N` and travels a distance of `6 cm` through the sand as it comes to a stop. If instead the cart runs into a patch of gravel on which the cart exerts an average horizontal force of `9 N` how far into the gravel will the cart roll before stopping?

Options

A. `2 N`
B. `3 N`
C. `6 N`
D. `18 N`

Answer

A

Explanation

The system consisting of the cart 's fixed , initial kinetic energy is the mechanical energy that can be transformed due to friction from the surface . Therefore , the loss of mechanical energy is
`Delta E _(mech) = - f_(k)d = - (6N) (0.06 m) = 0.36 J` This product must train the same in still for the rolling through gravel `- (f_(k)) (0.18m) = 0.36J`tells as `f_(k) = 2N`