To solve this problem, we must set up a system of equations. In this case, let's let Maggie's age be represented by the variable m and her brother's age be represented by the variable b. We are told that the sum of their ages is 24, which gives us our first equation: m + b = 24. We can construct our next equation from the first sentence of given information: b = 2m - 3. This makes our system of equations:
m + b = 24
b = 2m - 3
To solve, we are going to substitute the value for b in terms of m given by the second equation into the first equation for the variable b.
m + b = 24
m + 2m - 3 = 24
To simplify, we must first combine the variable terms on the left side of the equation using addition.
3m - 3 = 24
Next, we should add 3 to both sides of the equation to get the variable term alone on the left side of the equation.
3m = 27
Finally, we should divide both sides by 3 in order to get the variable m alone.
m = 9
Therefore, Maggie is 9 years old (using the first equation and substituting in this value you can find that her brother is 15 years old).
Hope this helps!
vi is going in the positive direction (up). (That's my choice). a (acceleration) is going in the minus direction (down). The directions could be reversed.
Givens
vi = 160 ft/s
vf = 0 (the rocket stops at the maximum height.)
a = - 9.81 m/s
t = ????
Remark
YOu have 4 parameters between the givens and what you want to solve. Only 1 equation will relate those 4. Always always list your givens with these problems so you can pick the right equation.
Equation
a = (vf - vi)/t
Solve
- 32 = (0 - 160)/t Multiply both sides by t
-32 * t = - 160 Divide by -32
t = - 160/-32
t = 5
You will also need to solve for the height to answer part B
t = 5
vi = 160 m/s
a = - 32
d = ???
d = vi*t + 1/2 a t^2
d = 160*5 + 1/2 * - 32 * 5^2
d = 800 - 400
d = 400 feet
Part B
You are at the maximum height. vi is 0 this time because you are starting to descend.
vi = 0
a = 32 m/s^2
d = 400 feet
t = ??
formula
d = vi*t + 1/2 a t^2
400 = 0 + 1/2 * 32 * t^2
400 = 16 * t^2
400/16 = t^2
t^2 = 25
t = 5 sec
The free fall takes the same amount of time to come down as it did to go up. Sort of an amazing result.
3. C 67.5 mi
4. A 65mi
5. B $270
A line parallel to the y-axis that passes through (77,88) is x = 77. There is no slope-intercept form of this equation if our coordinate system is based upon a horizontal x-axis and a vertical y-axis.
Answer:
See below
Step-by-step explanation:
58.4/9.6 can be rewritten as 58/10=5.8, so the decimal point will go between the first and second digits. Therefore, 58.4/9.6=6.083
