h(t)=-4.9t？ +6.5t+ 10

The derivative of height h with respect to time t represents the relationship between speed v and time:

∴v=h′(t)=-9.8t+6.5

The derivative of the required speed v with respect to time t is acceleration:

a = V′(t)=-9.8

Physically expressed as uniform acceleration,

Is the second derivative of distance with respect to time.