Question

Rachel is a stunt driver, and she's escaping from a building that is about to explode!
The variable d models Rachel's distance from her exit (in meters) t seconds after the cameras began recording the stunt.
d=-38t+220d
What is Rachel's speed?

Answer 1

Answer:

Given:

The variable d models Rachel's distance from her exit (in meters) t seconds after the cameras began recording the stunt. d = - 38t + 220

To find:

What is Rachel's speed?

Solution:

From given, we have,

The expression that represents the Richel's distance is given by,

d = - 38t + 220

where, d represents the distance in meters

          t represents the time in seconds

We know that, speed = distance by time.

Therefore, we need to differentiate the given equation w.r.t to time to find the speed.

Hence, we have,

d/dt (d) = d/dt [- 38t + 220]

| d/dt (d) | = | - 38 + 0 |

s =  d/dt (d) = 38 m/s

Therefore, the speed of Rachel is 38 m/s.

Step-by-step explanation:

Answer 2

Answer:

38 m/s

Step-by-step explanation:

As we know, speed v = dx/dt

Here the distance is a function of time, so

v = d/dt( 38t + 220)

v = 38 m/s

derivative of a constant (here 220) is zero.

derivative of a variable of N.x^(n) is (n × N) .x^(n - 1)

Here it is, N = 38, n = 1, since x = x¹