Answer:
true
Explanation:
because the roller coaster can't work without energy
On Earth, gravity adds 9.8 m/s to the downwsrd speed of any falling object, every second. Beginning from zero downward speed, the speed grows to (8 x 9.8) = 78.4 m/s downward after 8 sec.
Speed is just how fast the object is moving, while velocity is the speed and <em>direction </em>of the object.
edit* Direction would be something such as North, East, etc.
I think the correct answer among the choices listed above is option B. The acceleration of gravity is a constant equal to 9.8 meters per second squared. You can see that all things fall at this rate if there is no air resistance in a system or when in a vacuum.