What is the physical quantity represented by X and what is its SI - unit [y=(3.0m/s) + (X×2.0s)]

1) Acceleration
2) velocity
3) length
4) time

please hlp

Answer and I will give you brainiliest

After an atomic bomb has been dropped, the damage continues to get worse. why is this?

Trumpeter a holds a b-flat note on the trumpet for a long time. person c is running towards the trumpeter at a constant velocity. person b is running away from the trumpeter at the same rate. person d is standing still the whole time. which person hears a frequency that is lower than the b-flat?

True or false: the revolution of the earth creates day and night as it rotates around the sun