The displacement function of a rock thrown straight up in the air is given by f(t) = -2t2 + 15.7t meters, where t is measured in seconds. Find the total distance travelled by the rock when it reaches the ground.

Step-by-step explanation:

The height of the rock as it  reaches the ground is zero i.e f(t) = 0

Substitute into the function to get t first as shown;

f(t) = -2t^2 + 15.7t

0 = -2t^2 + 15.7t

2t^2 = 15.7t

2t = 15.7

t = 15.7/2

t = 7.85secs

Get the total distance travelled by substituting t = 7.85 into the modeled equation;

Recall that:

f(t) = -2t^2 + 15.7t

f(7.85) = -2(7.85)^2 + 15.7(7.85)

f(7.85) = -123.245+123.245

Hence the total distance travelled by the rock when it reaches the ground is 0m

sorry man i accidentally pressed yes my bad

step-by-step explanation: