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.
Answer:
32x4= 128 x 2= 256
Multiplied by two because you're adding the same equation
Step-by-step explanation:
Answer:
the first one not the second one
Step-by-step explanation:
Answer:
It'd help to show the graph but, count out how far it goes right, than count up how far it goes up, the first number is x, the second number is y
Step-by-step explanation:
The triangles in question 15 are proportional, so they are similar. Meaning that their angles are the same, so <B=<E, or <B=30 degrees.
For #17, the formula for the area of a circle is a=pi*r^2. The radius, in this instance, is 1/2 of 27, or 13.5. Plug it into the formula: a=pi*13.5^2. a=pi*182.25. If you want to simplify it further, a=572.265.
#19, same formula as #17. a=pi*r^2. a=pi*6^2. a=pi*36. a=113.04 or 113m^2.
#20, Wow this is a complicated one. Anyway, the area of the square in the middle is obviously 9m. The area of all of the circles is a=pi*1.5^2 DIVIDED BY TWO, since they're half circles. a=pi*2.25/2, a=7.065/2. a=3.5325. Since there are 4 of them, multiply that number by 4... 14.13. Add 9 to that to get the area of the whole figure: 23.13m(^2). Hope this helps.
