Answer:

Explanation:
Given:
- mass of car,

- distance of skidding after the application of brakes,

- coefficient of kinetic friction,

<u>So, the energy dissipated during the skidding of car:</u>
<em>Frictional force:</em>

where N = normal reaction by ground on the car


<em>Now from the work-energy equivalence:</em>


is the dissipated energy.
F = ma so u can plug in the given numbers and solve:
F = (2)(3)
B. transition metals for sure
Density can be any number, as long as it has the right units.
A unit of density has to be (a unit of mass) divided by (a unit of volume).
The most common one is gram/cm^3.