Assume that Emily starts from rest so that the velocity is zero at 0 hours.

Define the function v(t) for velocity in km/h, and t in hours.

Part A
From t=0 to t=4, v changes from 0 to 14.
Let v(t) = mt + b
The slope is
m = 14/4 = 3.5, and the y-intercept is
b = 0.
Therefore
v(t) = 3.5t, for 0 ≤ t ≤ 4

Fromt=4 to t=9, changes from 14 to 4.
Let v(t) = mt + b
The slope is
m = (4 - 14)/(9 - 4) = -2
Therefore
v = -2t + b
When t=4, v=14, therefore
14 = -2*4 + b = -8 + b
22 = b
v(t) = -2t + 22, for 4 < t ≤ 9.

Answer:
The equation for the velocity is
v(t) = 3.5t, 0 ≤ t ≤ 4
= -2t + 22, 4 < t ≤ 9

Part B
The equation for velocity is a piecewise function that is graphed as shown below. If we assume that the second part of the equation is valid at t=10, then
v(10) = -2*10 + 22 = 2 km/h

3 0

3 years ago

7.) There are about 9,987,000 people that live in Michigan. How do you write

aliya0001 [1]

D.) 9,987,000 becomes 9.987 x 10^6

7 0

3 years ago

Answer ASAP, Find the quadratic equations whose roots are ½ and -5/2

ArbitrLikvidat [17]

Answer:

4x^2+8x-5

Step-by-step explanation:

You work backwards to get (2x-1) which gets you the root 1/2 and (2x+5) which gets you the root -5/2 after this you foil what you have so (2x-1) times (2x+5). You do 2x times 2x which gives you 4x^2 2x times 5 which gives you 10x -1 times 2x which gives -2x and lastly -1 times 5 which gives you -5 now you combine like terms and get your final answer of 4x^2+8x-5

3 0

4 years ago