Answer:
Step-by-step explanation:
This is permutation question
<u>The formula for it: </u>
- N = b!/(b-s)!, where N- number of ways, b- number of books, s- number of slots
<u>Finding the answer:</u>
- N = 7!/(7-5)! = 7!/2! = 7*6*5*4*3 = 2520
Answer:
lol, hello again!
SA = 456 cm²
Step-by-step explanation:
small rectangle SA: 6*4 + 6*8 + 6*4 + 6*8 + 4*8 = 176
large rectangle SA: 2*14 + 2*8 + 2*14 + 2*8 + 8*14 + (8*14 - 8*4) = 280
Total SA = 176 + 280 = 456
60% of
35 is 21
Change the percentage (60) into a decimal by dividing it over 100:
Divide 21 by the decimal:
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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.
