A Levels Physics

When the brakes are applied on a vehicle moving at speed v, the distance d moved by the
vehicle in coming to rest is given by the expression
d = kv?
where k is a constant.
What is the unit of k expressed in SI base units?
A m-'s?
B ms2
c m's-2
D m-'s


Choice A is correct because:

The SI unit for distance 'd' is meters (m), and for speed 'v' is meters per second (m/s). 

Substituting these units into the equation d = kv2  gives m = k × (m/s)²

Solve for k : k = m / (m²/s²)

Simplify to get k = s²/m

Choices B, C, and D are incorrect because they state the wrong SI base units of k.

Physical Quantities and Units | 2014 - O/N - 9702/13 | Q1