Saturday
April 19, 2014

Posts by Damon


Total # Posts: 16,161

Physical
change of momentum = .14 * 38 average speed during stop = 38/2 = 19 time to stop = t =.15/19 = .00789 seconds F = change in momentum/time = .14*38/.00789 = 674 Newtons (ouch)

math
2.5 + 2 * 5 * tan 4 = 2.5 + 10(.07) = 3.2 inches

Physics
You are welcome :)

Physics
a = change in velocity /change in time = 3.5/t what is t? average speed is (3.5 + 0)/2 = 1.75 (that is part c) 1.75 t = 1.5 meters t = .857 second (that is part b) so a = 3.5 / .857 = 4.08 m/s^2 ( part a) when acceleration is constant, average speed during acceleration is (ini...

Math
speed at outer radius is the same w1 * r1 = w 2 * r 2 where w is radians/second so 2000 * 20/16

math
Or just figure out it is one quart per gallon in the first place :)

math
64 punch 64*5 punch ------- = ---------- 16 grape x oz grape x = 5*16 = 80 oz grape 80 oz * 1 quart/32 oz = 2.5 quarts

Physics
You are welcome.

Physics
.75 = (1/2)9.8*t^2 t^2 = .153 t = .391 second

Algebra 1 (Reiny)
4 * 3^4* 2^8/ (2^9 * 3^5 ) I think you mean it that way 4 /(2*3) 2/3

Math
(5/6) lb/bag * 12 bags = 10 pounds which is 5 of the 2 pound bags

math
x pounds of peanuts + 6 pounds cash = (x+6) pounds mix 2 x + 4 * 6 = 2.5 (x+6) 2 x + 24 = 2.5 x + 15 .5 x = 9 x = 18

Physics
http://www.jiskha.com/display.cgi?id=1391481178

physics
Fspring = -kx where x is extension up = -12 x N m = 0.35 kg Weight = .35 * 9.8 = 3.45 N How far will it drop before the force up = the force down? (the equilibrium position) -k (-x) + m g = 0 12 x = -3.45 x = -.2875 How much potential energy did it lose going from x = 0 to x =...

Physics
as with any parabola, it crosses the finish height twice, once on the way up and again later on the way down. We want it later coming back down so use the + sqrt and not the - sqrt for t

Physics
I solved the quadratic equation if a x^2 + b x + c = 0 then x = [-b +/- sqrt (b^2-4ac) ]/2a You had this in algebra I suspect. It works fine for 0 = (Hi-h) + Vi t - (1/2) g t^2

Physics
here is the method: http://www.jiskha.com/display.cgi?id=1391459618

Physics
I did this today as well. Click on links at the bottom of this page.

Physics
I just did this as well look at the bottom of this page and click on what looks familiar

Physics
scroll down

math
If you just want an estimate then about 60*10^-5 = 6 * 10^-4

Physics
p1 = 180 atm V1 = 45 m^3 p2 = 60 attm V2 = ? adiabatic p1 V1^gamma = p2 V2^gamma gamma = Cp/Cv for ideal monatomic about 1.67 180/60 = (V2/45)^1.67 ln 3 = 1.67 ln(V2/45) ln (V2/45) = .658 V2/45 = e^.658 = 1.93 V2 = 86.9 m^3

Physics
Thot = 266 + 273 = 539 Tcold = 115 + 273 = 388 That is all you need for Carnot efficiency eff = 100 (1 - Tc/Th) = 100(1-388/539) =28 percent

Physics
You are welcome :)

Physics
Yes, total momentum before = 0 total momentum after = 0 so m v + M V = 0 of course the little one has higher VEOLICIY but equal and opposite momentum

Science--Physics--check answers
7150 = F * 11 so F = 650 Newtons exerted by player since the velocity is constant that is exactly equal and opposite to the friction force Just use horizontal force. There is no up or down motion so vertical force does no work.

Physics
4 feet =1.2192meters (type **** 4 feet = meters ****into Google search box) h = Hi + Vi t -4.9 t^2 0 = 1.22 + 5.3 t - 4.9 t^2 or 4.9 t^2 - 5.3 t -1.22 = 0 solve quadratic t = [ 5.3 +/- sqrt (28.1+23.9) ]/9.8 use far answer t = 1.28 seconds 1.28 * 2.37 = 3.03 meters

Global Studies (Please help)
The others all fought like mad!!!!!

Global Studies (Please help)
Colorado Became a State August 1, 1876 That is 11 years after the Civil War ended.

Physics
10.4 t = (1/2)(2.97) t^2 t = 7 seconds 10.4 t = 72.8 meters

Physics
it did 126 -77 = 49 kcal work 100 * 49/126 = 38.9 %

Zero and Negative Exponents- Algebra
You are welcome

Zero and Negative Exponents- Algebra
3 a^4 c^3 / b^2 -1/(-5)^2 = -1/25 -1 z / y^7 -3n = -3(-24) = +72 (-2)^72 = 2^72 because even power = 4.7*10^21 very big number

Zero and Negative Exponents- Algebra
ANYTHING AT ALL^0 = 1

Physics
Excellent !

Physics
You are welcome.

Physics
The angular momentum vector resists directional change. <------- YES !!!! You should apply a force with your hand at the edge of the wheel.<------ YES!

Physics
a) 300 N•m YES (or JOULES) b) 2100 N•m YES (or Joules c) net force=200N and net work=2400N•m. *************** I get + for pull and - for friction so net = 175 - 25 = 150N Net work = 150 * 12 = 1800 Joules and 1800 = 2100 -300 indeed ********************* I'm...

Physics
2. A car slows from 108km/h to 90km/h over a course of 4.0s. THe force of the brakes was 1000N. What is the work done by the brakes on the car? My answer: 110 000N +++++++++++++++++++++++++++++++++++++++ How far? In constant acceleration, average velocity is (final +initial)/2...

Physics
1. A 50kg person is taking a ride on an elevator travelling up at a steady speed of 2.5m/s. Find the time fo the elevator trip if the elevator does 4900 J of work on the person. My answer: First I used the formula f=mg to find the force and got -490N. ************ - 490 N is g...

8gradescience
a

Physics
Good, you are welcome :)

Physics
north momentum = 10 m east momentum = 15 m final mass = 2 m final north v = 10 m/2 m = 5 m/s final east v = 15 m/2 m = 7.5 m/s |v| = sqrt(25+56.25) = 9.1 so yes

Physics
Once again, it is true again and again: Momentum before = momentum after if no EXTERNAL force on system, like here: 0 = 5 v + 3 * 3 v = -9/5 = -1.8

Physics
I guess both the cup and the water started at 30 C and ended at 35 C so they went up 5 C heat in = .6*.22*5+2.4*1*5 = 12.66 KCal heat out = 2.34 * c * (210-30) = 421 c KCal heat in = heat out 12.66 = 421 c c = 0.03 are you sure you added 2.34 kg of this stuff and not maybe 2.3...

Physics Please check my answers
3. I would say yes assuming g constant, p = rho g h Of course it also depends on velocity and acceleration 4. That is ARCHIMEDES !!!!!!! 5. Pascal did lots of things, but not Archimede's Principle 6, No, no, no !! look up "Bernoulli's principle. 7. is TRUE !!!! Be...

Physics
You are welcome.

Physics
momentum before = momentum after 1300 * 2 + 400 * 0 = 1700 v v = 1300 * 2 / 1700 v = 1.5 m/s

History8
I would also pick B but many of those works were after the Compromise of 1820 which kind of spoiled some of the good feelings.

math --- pls check my work!
Good :)

math --- pls check my work!
Yes, I agree with them

History8
Well, from that list I would pick Cooper.

History8
Louis La'mour with his silly westerns? I suppose but I wish the answer were Samuel Clemens.

physics
1.10 m - 0.98m = .12 m = 12 cm

typo ?
Box X ?

Physical sciences(Mechanics)
cos 30 = .866 3000 * .866 = 2598 N

Algebra
1/(-2)^(-72) = (-2)^(72) which is an even power so 2^72 = 4.722 *10^21

Physics Please check my answers
Gulp - re-read chapter ! 1. right sure, rolling ball 2. wrong, m r^2 does not change on Moon 3. wrong true, Moment = I alpha is F = m A 4. No, false , cross product perpendicular to both 5. right, vector 6. wrong, true, hinge works on torque (unless the latch is stuck :) 7. ri...

Physics
You are welcome. Nasty questions !

Physics
2. What is the speed of a 0.25kg ball if its kinetic energy is 15 J? my answer: 11m/s (1/2)(.25) * v^2 = 15 v = Yes, about 11 m/s 3. A ball is dropped off a high cliff. What quantity increases as the ball gets closer to the ground? my answer: I'm not too sure. It's eit...

NO! You fell for the trap!
1. A boy pushes down on a car rolling horizontally down the road. The boy pushes down vertically with 10N of force as the car rolls 3.0m horizontally. What work is done? my answer: 30 N•m (or would it be -30N•m?) NO, No, No !! Work is Force IN THE DIRECTION OF MOTION...

physics 1
at t = 0 Vx = 3.5 and Ax = 5.8 so at t = .5 Vx = 3.5 + 5.8*.5 = 6.4 Vy = 2.8 and Ay = -2 so at t = .5 Vy = 2.8 -2*.5 = 1.8 |v| = sqt(6.4^2 + 1.8^2) = 6.65 m/s tan theta = 1.8/6.4 so theta = 15.7 degrees north of east

You left out the acceleration vector
In fact you left all the quantities out ! acceleration of a particle moving only on a horizontal xy plane is given by ****** , where ************ is in meters per second-squared and t is in seconds. At t = 0, the position vector ************locates the paticle, which then has ...

Science
Well, I suppose they are all likely to differ but I agree sunlight is certainly the most obvious. How would phytoplankton function without sunlight for example?

SS
Yes Yes Yes D

physics
104 = (1/2)(9.8)t^2 t^2 = 208/9.8 = 21.2 t = 4.67 seconds

Physics
sorry. (1/2) 2 = 1 meter

Physics
2/1 = 1 meter

calculus
g = m t + b m = (17-8)/(47-28) = .4737 so g = .4737 t + b 8 = .4737 (28) + b so b = -5.263 so g = 0.4737 t - 5.263

physics
East: 5 - 2 /sqrt 2 = 3.5858 North: 2 + 2/sqrt 2 = 3.414 d^2 = 3.5858^2 + 3.414^2 d = 4.95 km

math
28/6 = 4 2/3 It is difficult to put 2/3 of a dog in a kennel so I would suggest something like 5 in 4 kennels 4 in the other two

math
.02 * 200 * 10^3 = 4 * 10^3 .01 * 200 * 10^3 = 2 * 10^3 .005*(540-400)*10^3 = 0.7*10^3 so (4+2+.7)*10^3 = 6.7*10^3 = 6700

Physics Help
Yes, assuming your vector is 10 degrees above the x axis in the first quadrant your answer is correct. Be sure you have it to 3 significant figures since both 1.00 and 10.00 are three significant figures. 1.00 cos 10.0 = 0.985 1.00 sin 10.0 = 0.174

physics
small r = 6,400 big r = 12,200 little force / big force = little r^2/big r^2 = 6.4^2/12.2^2 =.275

physics
average speed = (21 +30.9)/2 = 25.95 m/s so time = 191 m/25.95 m/s = 7.36 seconds a = change in velocity/change in time = (30.9-21)/7.36

physical science
work = m g h = 70 * 9.81 * 2.2 joules power = work in Joules /time in seconds = 70 * 9.81 * 2.2 / 1.2 in Joules per second which is WATTS

Physics
proportional to 1/R^2 double r, 1/4 force triple r, 1/9 force quadruple r, 1/16 force five times r , 1/25 force etc

calculus
I bet we want the maximum, but usually the foxes are included in these island problems. dP/dt = 0 at max = 120 -1.6 t^3 t^3 = 120 t = 4.93 months

math
6/3 = 2/1 = 48/24 so 24

solid mechanics
You really need pictures. This might help: http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/mohr_circle.cfm

CALCULUS
Whoops !

CALCULUS
x = y^2 - y y^2 - y + 1 = x + 1 (y-1)^2 = x + 1 y -1 = sqrt (x+1) y = 1 + sqrt (x+1)

physic
I thought I just answered this.

physic
You have treated the two pieces of tape the same way, ripping them off the same table. (at least I assume the same table. If not then who knows)

Physics
horizontal speed = u = 22 cos 63 the whole time Vi = 22 sin 63 at top v = 0 = Vi - g t where t is rise time t = Vi/9.81 average speed up = Vi/2 so top height = (Vi/2)t + 1.5 total time in air = 2 t so Sarah is u (2t) = 22 coa 63 (2t) meters from Julie

physics
8.6 = 4.9 t^2 t = 1.32 seconds to fall 8.6 meters v = g t = 9.81*1.32 = 13 m/s so speed = sqrt (169 + 1.3*2) =sqrt(169+1.69) =13.06 m/s

Physics
147*9.81 * 1.1 = 1586 useful work done 3620 -1586 = heat wasted = 2033 Joules convert those Joules to kilocalories by typing 2033 Joules = kilocalories into a Google search box and get 0.486 kilocalories

math
C(3,16) = 16!/[13!(3!) ] = 16*15*14/(3*2) = 16 *5*7 = 560

Calculus
when x gets really big positive this is y = 2 (big) / sqrt(big ^2) which is y = 2 when x gets really big negative y = 2 (-big number) / big number which is y = - 2 well, let's look at the derivative since they say so [ (x^2+x+1)2 - 2x(.5)(x^2+x+1)^-.5(2x) ]/(x^2+x+1) yuuk,...

math
110/130 = .846

Physics
You are welcome !

Physics
F = 65 * 9.81 Newtons energy = F*d = 65*9.81*6 Joules energy/unit time = power = 65*9.81*6/60 watts divide by .75 65*9.81*6/(60*.75)

Physics
You are welcome :)

Physics
4 meters is around 12 feet and 33 feet of water is about an atm but his is lighter than water, so total pressure will be about 1 1/4 atm including 1 atm at the surface .65 grams/cc = 650 kg/m^3 pressure = 4 * 650 *9.81 Newtons /m^3 or Pascals = 25,506 Pascals but that is gage,...

chemistry
hydrogen nucleus = 1 gram/mol = 1 amu * AV molecules/mol * 1.6605*10^-24 grams/amu so AV = 1 /(1.6605*10^-24 = .6022 * 10^24 = 6.022*10^23

physics
F = force up from scale F - m g = m a F = m(9.81+a) A) F = 95(9.81+1.8) = 1.103*10^3 N B) a = 0 so F = 95*9.81 = 932 N I get. Perhaps you are using 9.8 instead of 9.81 for g C) F = 95(9.8 - 1.3) = 807 N I do not know how you got strange answer

Calculus
point in first plane 0,0 something (0 , 0 , 10) d = | 10*0 -8*0 +2*10 -3 | /sqrt(10^2+8^2+4^2) = 17/13.4

Calculus
here is an example of how to do this: http://www.math.ucla.edu/~ronmiech/Calculus_Problems/32A/chap11/section5/718d65/718_65.html

physics
force = change in momentum /change in time = .015 (715/2.5)10^3 = 4.29 *10^3 = 4290 N

Calculus
vector normal to plane has direction 3 i + 2 j + 6 k line normal to plane through point is (1, -5 , 9) + (3, 2, 6) t where does that hit the plane? 3(1+3t) + 2(-5+2t) + 6(9+6t) = 5 solve for t go back and use that t to get x, y, z in plane x = 1+3t y = -5+2t z = 9+6t then d^2 ...

Pages: <<Prev | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | Next>>

Search
Members