The velocity will remain unchanged (Newton’s 1st Law) unless a force acts on it. If no friction force, then the velocity remains constant.
Answer:
On a roller coaster, energy changes from potential to kinetic energy and back again many times over the course of a ride. Kinetic energy is energy that an object has as a result of its motion. Traditionally, the coaster cars are pulled up the first hill by a chain; as the cars climb, they gain potential energy.
Answer:
speed of molecule ∝ 1/mass of molecule.
Explanation:
The velocities of the molecules depend on their masses. That's because if the molecules are large in size, their velocity is slower. Therefore their velocity is quicker when their size is small, since the molecules can move faster.
Therefore , it can be written as
speed of molecule ∝ 1/mass of molecule.
Answer:

Explanation:
Potential Energy= Kinetic Energy
Let
be the value of Kinetic Energy.
We know that

Make
the subject of the formula to get speed at the bottom of the hill.

Answer:
D) Higher Frequency
Explanation:
Higher frequency because it says a vehicle “towards” the officer