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 best answer to this question is D. a god scientific question should be based on observations instead of just imagination.
Hope this helps.
It is as a result of gravity. (D)
This is as stated by Newton's law of universal gravitation. That two objects in the universe attract one another with a force that is proportional to the product of their masses and inversely proportional to the square of the distance apart.
The constant of proportionality is the Universal Gravitational Constant.
G = 6.673 × 10⁻¹¹ Nm²kg⁻²
The basic relationship between wavelength

, frequency f and speed c of an electromagnetic wave is

where c is the speed of light. Substituting numbers, we find: