# Posts by Damon

Total # Posts: 31,631

math
1.07 and 0.75 first one first, second second one first :)

math
try it both ways

math ( help)
I know that a 3, 4 , 5 triangle is a right triangle but I can prove it easily anyway because 9 + 16 = 25 or in other words a^2+b^2=c^2 now multiply each side by 15 and get 45, 60 , 75 :)

Derivatives
You answered the question you asked, the function is differentiable for all real values of x The derivative is the slope of that straight line, 3 , so 3 and only 3

physics As
You have not posted all the information needed. 9.81 is the acceleration of gravity which has nothing to do with this. Why is there a 4 above 128? Please post the complete problem you were given as given. if acceleration and force is constant (1/2) v^2 = F d or initial kinetic...

Physics
F = m g = G m M/R^2 so g = G M/R^2 here G = 6.677 * 10^-11 R = 1.738*10^6 g is given = 1.62 solve for M

physics
the area under the curve is the distancee

Physics
yes

sorry, typo, 200
|A+B|^2 = 14.14^2 = 200 not 100 I did not use calculator, knew sqrt 2 = 1.414

Physics
A is perpendicular to B so A dot B = 0 AxBx + AyBy = 0 8 Bx + 6 By = 0 and A + B = (Ax + Bx)i+ (Ay+By)j |A+B|^2 = 14.14^2 = (Ax+Bx)^2+(Ay+By)^2 so (Ax+Bx)^2+(Ay+By)^2 = 100 (8+Bx)^2 +(6+By)^2 = 100 but we know By =-(8/6)Bx = -(4/3) Bx plug and chug.

Physics
well it is very difficult for A to be perpendicular to both B and C otherwise because j + k and 3 j+k just do not work :)

Physics
well, we know they are coplanar if t = 1 not if not

Physics
I assume you mean A = i+j+k Is A X B in the same direction as A X C? You can work it out but by inspection you can see that vector A is the same direction as vector C and therefore, A and B (or C and B) define a plane.

pre calc
The derivative is SLOPE of the curve at x It does not matter if you move the graph of the function up 7 units, the slope will be the same at each x. Graph it :)

algrebra 2
-4(3n+3)+2 -12n -10

calculus 2
integrate by parts int u dv = u v - int v du dv = cos 3 x dx so v = (1/3) sin 3x u = 3 x + pi du = 3 dx so u v - (3/3)integral of sin 3x dx put in your limits (3x+pi)(sin 3x)- int sin3x dx at pi/3 minus at pi/6

physics
density = mass / volume volume = mass/density I would do it all in cm^3 and grams 1 kg = 1,000 grams

physics
F = -k x x = A sin w t v = Aw cos wt a = -Aw^2 sin wt = -w^2 x but F = m a -k x = m(-w^2 x) so w^2 =k/m (2pi)^2/T^2 = k/m k = m (2pi)^2/T^2 = 0.200* (2pi)^2/0.25^2 k = 126 Newtons/meter now back to get A when at max x, energy = (1/2) k x^2 = (1/2) k A^2 so (1/2) k A^2 = 2 ...

Calculus
[1/(4x^3-12x^2)]d/dx[4x^3-12x^2] [1/(4x^3-12x^2)][12x^2-24x] [3x-6]/[x^2-3x]

Physics
There is no centripetal acceleration before the motion starts. Ac = V^2/R = omega^2 * R V = omega * R = 0 at start so Ac = 0 There is however an angular acceleration alpha = Torque/moment of inertia The tangential acceleration = alpha * R =================== When you stop ...

Science
power in Watts * time in seeconds = energy in Joules so 1225 * t = 727 t = (727/1225 )second

Science
https://www.jiskha.com/display.cgi?id=1512242770

Physics
few and far between.

math
s + g in bag at first s-1 = (1/7)(s+g-1) s = (1/5)(s+g-2)

Chemistry
you need 2 mols of H2 for every mol of O2 2 H2 + O2 -> 2 H2O or in this problem 4H2 + 2 O2 --> 4 H2O H2 is 2+16 = 18 grams/mol so 4 * 18 grams

Physics
did not check arithmetic but that is the right idea

math
multiply both sides of the equation by 5 5/5 = 1 4*5 = 20

Doing just one. The rest are similar.
we know 5*3 is 15 and two 15s is 30 so (5x-3)(5x-3) = 0 so 5x-3 = 0 x = 3/5 twice because both solutions are the same. That means the vertex of the parabola is on the x axis at x = 5

I am no historian but for 2 I would have picked D because the act is about voting rights and for 3 I would have picked C because unlike blacks or indigenous Americans, the Chinese railroad laborers were not citizens and that was used as an excuse.

As Physics
Your problems are all the same. You do not seem to have tried any. I will outline this one, period. Initial momentum: P = 4,000 * 2 + 100,000 * 0 = 8,000 That is of course the final momentum as well. 8,000 = (4,000+100,000) v Since they stick together, v is the final speed of ...

math
5 mi/3 in look at squares on map 5 miles * 5 miles = 3 in * 3 in so 25 mi^2/9 in^2 45 in^2 * (25 mi^2/9 in^2) = 45*25/9 mi^2 = 125 mi^2

Math
I agree that is probably what they want but I could see it as y+5 = -2/ [5(x+3)] which is wrong so I was reluctant to pick one of the listed answers

Math
(y+5)/(x+3) = -2/5 y+5 = (-2/5)(x+3)

Math
you could use 1+1+1+1+1

PLZ
let z = x^2 then you have 3 z^2 -27 z -1200 = 0 or z^2 - 9 z - 1200 = 0 z is about 40 or -30 (you can do quadratic accurately) so x = +sqrt 40 or - sqrt 40 or +i sqrt 30 or -i sqrt 30

No way
We are tutors, our job is to help people learn, not to help them bypass learning.

Physics
F is up, + F - m g = m a F = m(g+a) = 40 (9.81+3)

Math
same numerator, smaller denominator 1/4 is greater than 1/8 :)

No way !!
You are just guessing. Think!

Physics
F = m a braking so - -6000 = 1100 a a = -5.45 m/s^2 v = Vi + a t at stop 0 = 15 -5.45 t t = 2.75 seconds to stop average speed during stop = 15/2 = 7.5 m/s d = 7.5 * 2.75 = 20.6 meters

typo ?
I bet you mean 10x+10y+20z=1850 20x+20y+10z=2200 20x+10y+10z=1500 get rid of x and y in first two by multiplying first eqn by 2 20x+20y+40z=3700 ................> 30 z = 1500 so z = 50 20x+20y+10z=2200 ========================= then third and first 20x+10y+10z=1500 >>...

pre-algebra
x + (x-5) = 31 2 x - 5 = 31 2 x = 36 x = 18 x-5 =

History
By the way, I am not happy that they left out cod and halibut.

History
What unhealthy weed was exported from Jamestown area? What not warm when wet cloth was exported from the southern states? What unhealthy additive was exported from the Caribbean Islands?

math
140 * 16

Physics
well force up = force down force up at knee = Fk at x = 0 Force up on rope = T at x = .65 weight down at center = 2.6*9.81 at x = .435 forces up = weight down Fk + T = 25.5 N moments about knee = 0 0 = .65T - 25.5*.435 so T = 17.1 Newtons if this is done by a mass on a pulley ...

Physics
loss of potential energy = m g h = 3*9.81* 7 = 206 Joules = translational Ke + rotational Ke = (1/2) m v^2 + (1/2)I omega^2 Note I = (2/5) m r^2 v = omega r so 206=(1/2)m v^2 + (1/2)(2/5)m r^2 v^2 412 = 1.4 *3 v^2 v = 9.9 m/s then calculate (1/2) (2/5)(3) v^2

physics
You are welcome.

physics
r = 0.56/2 = 0.28 meters period = .75 s so the block goes 2 pi r meters in 0.75 seconds v = 2 pi *.28 / 0.75 = 2.35 meters/second F = mass * centripetal acceleration = m v^2/r = 1.5 * 2.35^2/.28 = 29.5 Newtons

Physics
v = initial v + a t v = 5 - 0.84 (15)

Physics
Interesting, I just answered some of these posted later under different names.

Science
Ah well, I saw the question too late.

Science
ah, I disagree. The predator highest on the list usually is big in size( whale :) but is small in population numbers. A hawk eats a lot of songbirds.

Science
You are welcome, good luck. Either way you could do a good poster.

Science
it says "or" not "and" so I would describe how to reduce use of it, or how to use it more than once (steel spoon instead of plastic :), or how to recycle it for use as something else.

math help
3 y - 5 = 3 3 y = 8 y = 8/3 =============== or do you mean (y-5)/3 = 1 y - 5 = 3 y = 8

physics
which has the lowest ratio of surface area to volume? let volumes all be 1 sphere v = (4/3) pi r^3 = 1 then r = [ 3/(4pi) ]^1/3 r = .620 a = 4 pi r^2 = 4.836 cube v = s^3 = 1 so s = 1 a = 6 s^2 = 6 (so cools faster than sphere) cylinder LOL, depends on height to radius but pi ...

physics
I think the arc length is the distance along the circumference here. r theta = 2.55 theta = 2.55/2 = 1.275 radians so I get omega = 1.275/2.30 = 0.554 radians/second he went from 0 to 0.554 rad/s so his average omega is 0.277 rad/s so v = omega r = 0.277 * 1.75 = 0.485 meters/s

Math
12 km/hr * 1000 m/km * 1 hr/60 min = 200 meters/min 10 km/hr = 166.7 meters/min distance = d d = 200 (t-4) = 200 t - 800 d = 166.7(t+6) = 166.7 t + 1000 33.3 t = 1800 t = 54.1 minutes d = 200(54.1) - 800 = 10,010 meters = 10 km check 200(54-4) = 10,000 167(54+6) = 10,000

physics
F = - G m M/r^2 work done from R to infinity F dr = G m M/R so G M m/R^2 = Ke at surface = (1/2)m v^2 v^2 = 2 G M/R G = 6.67 * 10^-11 M = 7.4 * 10^22 kg R = 1.74^10^6 meters plug and chug

Math
2p or often online here 2*p or 2 x p but that is confusing using x both for multiplication symbol and also possibly for a variable name

Math
y-3

Science

Physics
850/5 = 170 Newtons (actually it is closer to 1/6 ) Remember the mass is the same on both earth and the moon and weight is m * local g

AP physics multiple choice
Assuming that the collision happened so fast that the machine swinging the bat put no work in during the collision the angular momentum (of the entire bat/clay system)does not change. The moment of inertia is a little higher due to the mass of the clay so the angular velocity ...

physics
in normal operation of a bulb 200 Watts = V^2/R = 120^2/R so R = 72 Ohms now we have two in series so V = 120/2 = 60 volts again watts power = V^2/R = 60^2/72 = 50 watts

history
Wait a minute. It is not asking for his role in the war of Texas independence against Mexico but for his role in joining the United States as a state rather than as an independent republic.

Math
Draw a long line, mark a point O on the line mark one side of O length a mark the other side length b the total length is then (a+b) Draw a short line through O perpendicular to the first one Draw a short line through O, perpendicular to the long one . Lengths c and d, total ...

Math
you mean there is a path of constant width between the garden and the fence? well 23.5 - 14.5 = 9 17.75 - 8.75 better be 9 :) half of 9 is the path width 4.5 feet

Math
well right off you see where they cross 5x-7 = 6x+2 so -9 = 1 x so x is -9 at the intersection then at that intersection y = 6x+2 = -54 + 2 = -52 You can check that with the other equation y = 5x-7 = -45 - 7 = -52 sure enough

Oh ?
Please look at those answers again and tell us which one makes sense and which three are simply crazy.

Rachel Carson

I agree.

PreCalc
first division -> a+b+c-1 = 14 second division -> c-a-b+1 = 0 third division-> have to go, continue ;)

Physics
work done = 9.81*200 * 2 power = work done / time = 9.81*200 *2/2.2 Watts Wow, like a horse

physics
vertical problem: normal force = weight - string up force = 890 - T sin 30 = 890-.5 T horizontal problem: T cos 30 - .2(890-.5T) = (890/9.81) (0.8) solve for T

Math
3 meters = 300 cm 8 * 40 = 320 cm need 20 cm more than I have

Math
300 / 50 = 6 with nothing left over

Calculus
L = 2 w V = L w h = 2 w^2 h = 10 so w^2 h = 5 base area = L w =2 w^2 base cost = 18 w^2 ends area = 2 w h ends cost = 300 w h sides area = 2 L h = 4 w h sides cost = 600 w h total cost = 900 w h + 18 w^2 but h = 5/w^2 c = 900 w (5/w^2) + 18 w^2 c = 4500/w + 18 w^2 dc/dw = -...

Calculus
do you mean base = 2 r = 10/(1+pi/4) ?? if that is correct then 2r + 2h + pi r = 20 total height = h + r 10/(1+pi/4) + 2 h + pi(5/(1+pi/4) = 20 10 + 2h(1+pi/4) +5 pi = 20 2h(1+pi/4) = 10-5pi h = (10-5pi)/(2+pi/2) then to get total height add r r+h = 5/(1+pi/4) + (5-2.5pi)/(1+...

Calculus
y = m x + b 2 = 6 m + b m=(2-b)/6 when y = 0 x = -b/m so Area = (1/2)b(-b/m) A = -b^2/2m A = -3b^2/(2-b) dA/db = [(2-b)(-6b)+3b^2(-1)]/bot^2 =0 for min or max 3 b^2 = -12b + 6 b^2 3 b^2 = 12 b b = 4 (or zero of course) so y intercept is 4 m = (2-b)/6 = -2/6 = -1/3

physics
n1 sin T1 = n2 sin T2 n1 = 1.000 n2 = 1.655 1.000 sin T1 = 1.655 sin 24 sin T1 = .673 T1 = 42.3 degrees

I see your other problms, try them
I see your other problems. They are really just like this one. Try them.

Physics
component of weight down plane = m g sin 35 friction up plane = .2 m g cos 35 so force accelerating m down plane = m g (sin 35 - .2 cos 35) a = force/m = g(sin 35 - .2 cos 35) distance =(1/2) a t^2 = 8 meters solve for t

math
well, 5x is "like" -2x and -10 is "like + 10 so "combine" them and by the way 3x - 0 = 9

Social Studies
I assume that each reply will be in the form of a doctoral dissertation.

Math
NOT multiplied by 2 radius SQUARED on the right r times r

Math
no, the radius is the radius it is r^2 = 0.25 so r = 0.50 (x-k)^2 + (y-h)^2 = r^2 center at (h,k) radius of r

Math
I do not know what you are talking about with the first one. It is nott an equation the second one is a circle with center at (3,7) and radius of 0.50

World History
She and Martin Luther used to debate in the hallway. I listened at the door.

Physics
u = -6.65 m/s u t = -20 + 3 t 20 = (3 + 6.65)t t = 2.07 secs how high? h = 12.45(2.07) - 4.9(2.07)^2 = 25.8 - 21 = 4.8 meters so 4.8 = Vih (2.07)-4.9(2.07)^2 Vih = 12.5 meters/ second check my arithmetic !

maybe
If the elevation angle of the cannon is 38.5 degrees then the horizontal velocity of the cannon ball relative to earth is u = 19 - 10 - 20cos 38.5 forever Its location relative to earth from the time of firing is x = u t the initial vertical velocity of the cannon ball is Vi...

physics
horizontal U = 20 cos 25 for the whole trip so range = 20 cos 25 * time in air vertical initial speed up = Vi = 20 sin 25 v = Vi - g t where t is time up so t = Vi/g = (20/9.8) sin 25 time down = t = time up so time in air = 2 t so range = 2 t * 20 cos 25 for max height, ...

mathematics
(1/2) L B H

CAlculuss
so y = 2/x x^2 - 2 (2/x)^2 = 2 x^2 - 8 /x^2 = 2 x^4 - 2 x^2 = 8 let z = x^2 z^2 - 2 z - 8 = 0 (z -4)(z+2)= 0 z = +4 or z = -2 so x^2 = +4 or x^2 = -2 x = +2 then y = 1 x= -2 then y = -1 x = 2 i then y = 2/2i = -i x = -2i then y = +i put these all back in to check

Hey, one is enough
I just did the other one, same deal average force = impulse/time

physics
(1/2) m v^2 = m g h so v = sqrt(2 g h) impulse = m v = m sqrt(2 g h) = 0.056 sqrt (2*9.81*5.40)

Physics
initial I = .00250 * 2.5 = final I = .00250 * Vp + .00500 * Vn Initial Ke = final K =(1/2)(.00250)(6.25) =(1/2)(.00250)Vp^2 + (1/2) (.00500) Vn^2

Physics
100*8.5 = 175* Vnorth 75*7.5 = 175*Veast |V| = sqrt(Vnorth^2+Veast^2) T is angle East of north (note, compass angle, not math angle) tan T = Veast/Vnorth

Physics
inertia before collision: P = 70*15 + 4.7 * 0 Inertia after collision also = P = (74.7)v compute v kinetic energy after collision = Ke = (1/2)(74.4)v^2, do not bother to compute because at max distance up slope 74.4 g h = that Ke and when it comes back down Ke is that Ke again...