Final answer:
The value of d in the equation d=at² when acceleration a is 9.8 m/s² and time t is 4 seconds is 156.8 meters.
Step-by-step explanation:
In the equation d=at², we are asked to find the value of d when a is 9.8 m/s² and t is 4 seconds. Substituting the given values into the equation yields:
d = 9.8 m/s² * (4 s)²
d = 9.8 m/s² * 16 s²
d = 156.8 m
The value of d when a is 9.8 m/s² and t is 4 seconds is 156.8 meters.