Answer:
(a) Y = 129.3x (b) It is an estimate as it may not be a true reflection of a student's height
Step-by-step explanation:
(a) Estimate of the mean height is the sum of the heights of all the students divided by the total number of students.
The question however needs more information for its estimation as 129.3cm is representative and may be the mean height but it was not stated.
However, assuming it is the mean height,
Let the total number of students be x
while Y is the sum of all individual student heights
Mathematically, mean = Y/x
Therefore 129.3 = Y/ x
implying that Y = 129.3x
(b) It is an estimate because computation of the mean gives an average which may not be an exact value. For example, the mean here is 129.3 whereas there will be many heights greater than that and some lesser than that and obviously, there may be no student with height of 129.3 hence it is an estimate.
Answer:
Step-by-step explanation:
Since triangle ADE and triangle ABC are similar, that means their sides are proportional, thus we get the equation
Thus the value of x is 4
Answer:
second option is correct onee
Step-by-step explanation:
mark me brainliest
The number is already in prime factored form. The prime factors are 2, 3, 5, and 7. If we multiply everything out then we end up with 2100
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.
