Mathematics, 05.05.2020 16:45 kkqueen01

A rock is dropped off a ledge on the moon according to the
formula d(t) = .7t^2, find the average speed, in meters per
second, between 4 and 8 seconds after it was dropped.

Answers: 2

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Answer from: margaret8800

8.4m/s

Step-by-step explanation:

the information we are given is:

initial time: $t_{1}=4s$

final time: $t_{2}=8s$

thus, the interval of time is: $t=t_{2}-t_{1}=8s-4s=4s$

according to the statement, the distance at a certain time is given by:

d(t)=0.7t^2

To find the average distance we need to find first the total distance traveled in those 4 seconds .

At a time of 4 seconds ⇒ $t_{1}=4s$

the distance at that time is:

$d(4)=0.7(4)^2\\d(4)=0.7(16)\\d(4)=11.2m$

also, the distance at a time of 8 seconds ⇒ $t_{2}=8s$

and the distance at this time is:

$d(8)=0.7(8)^2\\d(8)=0.7(64)\\d(8)=44.8m\\$

Now we can find the distance traveled between 4 and 8 seconds:

$d=d(8)-d(4)\\d=44.8m-11.2m\\d=33.6m$

and finally we use the formula for the average speed:

$s=\frac{d}{t}$

where is the distance traveled in time:

$s=\frac{33.6m}{4s} \\s=8.4m/s$

the average speed in meters per second: 8.4m/s

Answer from: ymuttmutt7628

8.4m/s

Step-by-step explanation:

Speed or velocity is defined as the change in distance of a body with respect to time. It is expressed as:

Speed = distance/time

Given distance d(t) = 0.7t²

When t = 4secs

d4) = 0.7 × 4²

d(4) = 11.2m

At t = 8secs

d(8) = 0.7× 8²

d(8) = 44.8m

Since speed = distance/time

Speed at t = 4secs = 11.2/4

= 2.8m/s

Speed at t = 8secs = 44.8/8

= 5.6m/s

average speed, in meters per seconds between 4 and 8 seconds after it was dropped will be ∆d/∆t

= 44.8-11.2/8-4

= 33.6/4

= 8.4m/s

Answer from: Quest

take it another

Answer from: Quest

answer: a video game has three difficulty levels: easy, medium, and expert. the game's scoring works in such a way that a player has to score a fixed number of points to advance to the next level, and then the scoring starts over. the total score needed to clear all three difficulty levels is 7,500. two times the number of points needed to clear the easy level is 500 more than the number of points needed to clear the medium level. twice the number of points needed to clear the medium difficulty level is 1,500 more than the number of points needed to clear the expert level. if x, y, and z represent the easy, medium, and expert levels, respectively, and a is the coefficient matrix of the system of equations modeling this situation, identify the inverse matrix, a-1, and the solution matrix, x, of the system of equations.

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A rock is dropped off a ledge on the moon according to the
formula d(t) = .7t^2, find the aver...

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