If u mean pressure, pressure = Force/Area
Correct me if I am wrong :D
The example says skateboard. Something to do a vehicle. Motorcycle or bike are both vehicles which uses the following energy.
<em>D. Less luminous than those on the right []</em>
<span>The definitions of the principal axis, centre of curvature , radius of curvature , and the vertex , of a convex mirror are analogous to the corresponding definitions for a concave mirror. </span>