calculate the coefficient of kinetic friction for tyre rubber on the road surface

Answer 1

You have to have much more info to do this. On way is to do braking distance.

Vf^2=0=Vi^2+2 Forcebraking/masscar)*distancestopping)

and forcebraking=masscar*coefficent

so this ends up as

2*coefficent*distance=initialvelocity^2
and you solve for the coefficent.

Answer 2

hearing rattles from a snake, a boy make two rapid displacements of magnitude 1.8m and 2.4m in sketches show how the two displacements might add up to give magnitude of