Different measurements are expressed in different units. choose the correct si units for the following types of
measurement
the si units for measuring the velocity of the car:
the si units for measuring the acceleration of the car:
the si units for measuring force:
the si units for measuring mass:

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?

It is really hard for me right know

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.