That is meters per second, same as velocity.
Gravitational force is given by, 
Where, m and M are the masses of the objects, R is the distance between them and G gravitational constant.
Gravitational force of the star on planet 1, 
Gravitational force of the star on planet 2, 
Ratio, 

Therefore, the gravitational force of the star on the planet 1 is three times that on planet 2.
Longitudinal waves transfer energy parallel to the direction of the wave motion
Answer:
took longer to complete one oscillation, that means its PERIOD increased, and the distance between the peaks of the graph would be longer.
line would be less. the period of oscillation would have any effect on the graph