Answer:
speed is affected by the medium in wich the wave travels.
Explanation:
The speed of a wave is affected when traveling in different medium, depending on the medium in which the wave travels it can go faster or slower, or not even be able to travel in that medium.
For light waves, the denser the medium through which the wave travels, the slower it will go through it, as there is more resistance to the light particles.
And in waves like sound, which instead of particles is a vibration or disturbance in the medium, they travel faster in denser mediums such as metal, because the disturbance is transmitted more efficiently thanks to how close together that the particles are in the metal, This is why sound does not travel in a vacuum; there are not even particles to transmit the vibration.
There's no such thing as one balanced force or one unbalanced force.
If ALL of the forces in a GROUP of forces acting on the same object
all add up to zero, then we say that the GROUP of forces is balanced.
If they don't, then the GROUP of forces is unbalanced.
Two or more forces can be balanced or unbalanced.
One force can't.
Velocity is defined by rate of change in the position
which we can also write as

while acceleration is defined as rate of change in velocity

so acceleration and velocity both are rate of change in position and rate of change in velocity with respect to time respectively
out of all above statement the correct answer must be
<u>Acceleration equals change in velocity divided by time. </u>