True or False? -2.08 would be just to the right of -2 on the number line.

A 4-centimeter rod is attached at one end A to a point on a wheel of radius 2 cm. The other end B is free to move back and forth

zloy xaker [14]

Answer:

Step-by-step explanation:

The triangle that was formed has radius 2:

hypotenuse = 2

adjacent = x = 2*cosθ

opposite = y = 2*sinθ

from the first picture on the left, we see that the rod has length of 4.

We then use pythagoras theorem with respect to the triangle formed with the rod, i.e, the opposite leg, and the length of the remaining side (say, L), we have:

2²sin²θ +L² = 4²

On rearranging and making L subject of formula, we have

L = √(16 - 4sin²θ)

or

L = 2√(4 - sin²θ)

Also, the distance of point B is from the center of the circle, and it is:

2cosθ + 2√(4 - sin²θ)

We know that

3.5 revolutions per second means 3.5(2π) per second.

or

7π radians per second

So we try to write the angle formed as:

θ = 7π*t

where t is the time in seconds.

(a)

2cos(7πt) + 2√(4 - sin²(7πt))

at t = 1/21 we substitute for t, and then

2cos(π/3) + 2√(4 - sin²(π/3))

= 1 + √13 or approximately 4.6

(b)

(c)

B = 2cos(7πt) + 2√(4 - sin²(7πt))

dB/dt = - 14πsin(7πt) - { 14π*cos(7πt)sin(7πt)/√(4 - sin²(7πt)) }

4 0

3 years ago

A worm takes 19 seconds to travel 25 cm , How many groups of 25 cm are in 1 meter ? u guys don't need to help me but if u would

Sedbober [7]

Answer:

Step-by-step explanation:

we know that 100 cm are equal to 1 meter

there are 4 "groups" of 25 cm in one meter

the worm needs 76 seconds to travel a meter, in case you need to know that

6 0

3 years ago

The number of entrees purchased in a single order at a Noodles & Company restaurant has had an historical average of 1.7 ent

SOVA2 [1]

Answer:

$t=\frac{2.1-1.7}{\frac{1.01}{\sqrt{48}}}=2.744$

$p_v =P(t_{(47)}>2.744)=0.0043$

If we compare the p value and the significance level given $\alpha=0.02$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can conclude that the true mean is higher than 1,7 entrees per order at 2% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=2.1$ represent the mean

$s=1.01$ represent the sample standard deviation

$n=48$ sample size

$\mu_o =1.7$ represent the value that we want to test

$\alpha=0.02$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is higher than 1.7, the system of hypothesis would be:

Null hypothesis: $\mu \leq 1.7$

Alternative hypothesis: $\mu > 1.7$

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{2.1-1.7}{\frac{1.01}{\sqrt{48}}}=2.744$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=48-1=47$

Since is a one side test the p value would be:

$p_v =P(t_{(47)}>2.744)=0.0043$

Conclusion

If we compare the p value and the significance level given $\alpha=0.02$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can conclude that the true mean is higher than 1,7 entrees per order at 2% of signficance.

4 0

4 years ago

Read 2 more answers

A tape diagram. There are 65 students out of 100 students who ride the bus. There are question mark students out of 800 students

SVEN [57.7K]

Answer:

800÷100 = 8

65×8=520

$\frac{520}{800}$