<u>Answer</u>
D. Base units
<u>Explanation</u>
Basic units are also called fundamental units. They are the standard units agreed internationally for measurements. Most of these measurements are taken from the ground and they are used to derive other units. They are seven in number. There are:
The metre (m)
The kilogram (kg)
The second (s)
The ampere (A)
The kelvin (K)
The candela (cd)
The mole (mol)
This state of motionlessness occurs because all of the kinetic energy in the car is absorbed by the spring in the form of elastic potential energy. The mathematical representation is:
1/2 mv² = 1/2 kx²
25m = kx², where m is the mass of the cart, k is the spring constant and x is the spring's extension.
The answer to your question is Speed