Lisa took a survey of her classmates' favorite sport and recorded their genders. The results are in the table below:

Find the value of y-7 when y=15

ivann1987 [24]

Answer:

8

Step-by-step explanation:

y-7 when y=15

15-7=8

4 0

3 years ago

A family makes rods by cutting plastic pipes that are 5 feet long into 8 rods, how long are each rod?

Sauron [17]

Answer:

Five feet?

Step-by-step explanation:

N/A

7 0

2 years ago

Astrid travels 130 km in 2 hours and then at 85 km/h for another 3 hours to reach her

Pie

Answer:

$\huge\boxed{\sf Speed = 77\ km/hr}$

Step-by-step explanation:

<h3><u>Formula to be used in the question:</u></h3>

Speed = Distance / Time

<h3><u>Distance for the first 2 hours:</u></h3>

= 130 km

<h3><u>Distance for the next 3 hours:</u></h3>

Speed = 85 km/h

Time = 3 hours

So,

Distance = Speed × Time

Distance = 85 × 3

Distance = 255 km

So,

<h3><u>Total distance from home to destination:</u></h3>

= 130 + 255

= 385 km

<h3><u>Speed on the return journey:</u></h3>

Total distance = 385 km

Time = 5 hours

Speed = Distance / Time

Speed = 385 / 5

Speed = 77 km/hr

$\rule[225]{225}{2}$

4 0

1 year ago

A small rocket is fired from a launch pad 10 m above the ground with an initial velocity left angle 250 comma 450 comma 500 righ

jonny [76]

Let $\vec r(t),\vec v(t),\vec a(t)$ denote the rocket's position, velocity, and acceleration vectors at time $t$ .

We're given its initial position

$\vec r(0)=\langle0,0,10\rangle\,\mathrm m$

and velocity

$\vec v(0)=\langle250,450,500\rangle\dfrac{\rm m}{\rm s}$

Immediately after launch, the rocket is subject to gravity, so its acceleration is

$\vec a(t)=\langle0,2.5,-g\rangle\dfrac{\rm m}{\mathrm s^2}$

where $g=9.8\frac{\rm m}{\mathrm s^2}$ .

a. We can obtain the velocity and position vectors by respectively integrating the acceleration and velocity functions. By the fundamental theorem of calculus,

$\vec v(t)=\left(\vec v(0)+\displaystyle\int_0^t\vec a(u)\,\mathrm du\right)\dfrac{\rm m}{\rm s}$

$\vec v(t)=\left(\langle250,450,500\rangle+\langle0,2.5u,-gu\rangle\bigg|_0^t\right)\dfrac{\rm m}{\rm s}$

(the integral of 0 is a constant, but it ultimately doesn't matter in this case)

$\boxed{\vec v(t)=\langle250,450+2.5t,500-gt\rangle\dfrac{\rm m}{\rm s}}$

and

$\vec r(t)=\left(\vec r(0)+\displaystyle\int_0^t\vec v(u)\,\mathrm du\right)\,\rm m$

$\vec r(t)=\left(\langle0,0,10\rangle+\left\langle250u,450u+1.25u^2,500u-\dfrac g2u^2\right\rangle\bigg|_0^t\right)\,\rm m$

$\boxed{\vec r(t)=\left\langle250t,450t+1.25t^2,10+500t-\dfrac g2t^2\right\rangle\,\rm m}$

b. The rocket stays in the air for as long as it takes until $z=0$ , where $z$ is the $z$ -component of the position vector.

$10+500t-\dfrac g2t^2=0\implies t\approx102\,\rm s$

The range of the rocket is the distance between the rocket's final position and the origin (0, 0, 0):

$\boxed{\|\vec r(102\,\mathrm s)\|\approx64,233\,\rm m}$

c. The rocket reaches its maximum height when its vertical velocity (the $z$ -component) is 0, at which point we have

$-\left(500\dfrac{\rm m}{\rm s}\right)^2=-2g(z_{\rm max}-10\,\mathrm m)$

$\implies\boxed{z_{\rm max}=125,010\,\rm m}$

7 0

2 years ago

Line f has a slope of -9/7. Line g is perpemdicular to f. What is thr slope of line g

Dmitriy789 [7]

The slope of line F is 9/7 without the negative symobolb

8 0

2 years ago

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