The Height of an Object T Seconds After It Is $s ( t ) = - 4.9 t ^ { 2 } + 250$

Multiple Choice

The height of an object t seconds after it is dropped from a height of 250 meters is $s ( t ) = - 4.9 t ^ { 2 } + 250$ . Find the time during the first 8 seconds of fall at which the instantaneous velocity equals the average velocity.

A) 32 seconds
B) $19.6$ seconds
C) $6.38$ seconds
D) 4 seconds
E) $2.45$ seconds