# Posts by Damon

Total # Posts: 31,636

**math please answer quick!!!**

yes

**physical science**

I see, thanks, you had me pretty puzzled :)

**physical science**

You did 4 right but missed 2? That makes no sense.

**physics**

Force * time = impulse or change of momentum a) so Impulse = 970*0.0088 b) As I said, impulse IS change of momentum c) initial momentum = -.145*32 (calling negative speed from pitcher to batter, positive from batter to center field) The change of momentum is up in parts a and ...

**physics**

in kg, meters, seconds: bullet mass = 0.0024 kg 0.0024 v = (0.650 + 0.0024)(0.96) v will be in METERS/second

**physics**

8340(14.3)+6420(8.78) = (8340+6420)v Ke initial = (1/2)(8340)(14.3^2) + (1/2)(8340)(8.78)^2 Ke final = (1/2)(8340+6420) v^2 it better be less.

**physics**

BSc in Physics, Ocean Engineering professor, retired. You are welcome. and error percent = 100 (ball energy/total energy)

**physics**

1100 v + 6.2 * 190 = 0 energy of ball = (1/2)(6.2)(190)^2 energy of cannon = (1/2)(1100) v^2 total = sum of those percent = 100 (ball energy/cannon energy) No, I do not think it is confusing.

**physics**

force = rate of change of momentum change of momentum of vehicle + change of momentum of fuel = 0 in one second: 10,000 (change of vehicle speed) = 1.4*240 = 336 kg m/s so change of vehicle momentum per second =336 kg m/s^2 = Force (answer #1) acceleration = change of vehicle ...

**Physics**

You have got to be kidding F = k x F = 200 N x = 0.021 meter

**Physics some kind of a joke?**

Hey, Google "conservation of momentum" 0.05 m/s * 0.17 kg = v * 0.16

**see above**

....

**Algebra I**

Now let me see. 3^-2 = 1/3^2 = 1/9 (-3)^-2 = 1/(-3)^2 = 1/9 3^-1 = 1/3^1 = 1/3 (-3)^-1 = 1/(-3)^1 = -1/3 well, looks like I agree with you

**Physics**

mg + k x 0.50 * 9.81 + 43.8 * 0.037

**Add maths**

(x+2)(x+3) =x^2 + 5 x + 6 so (a+3) = 5 -2b =6 a = 2 b = -3 check x^2 + 5 x + 6 = 0 (x+2)(x+3)=0

**math - bearings**

first leg north +1.5 cos 30 east +1.5 sin 30 second leg north -3.5 cos 20 east +3.5 sin 20 third leg north +6.25 sin 30 east -6.25 cos 30 so where are they from start? north 1.5 cos 30 - 3.5 cos 20 + 6.25 sin 30 east +1.5 sin 30 +3.5 sin 20 - 6.25 cos 30 d = Total distance = ...

**Math**

LOL, I think she just wants the part you see from above If D is 14 then the slimy area has diameter of 12 because you take and inch off each side. so area of a circle = pi d^2/4 (pi/4)(14^2-12^2) sure enough 40.8

**math**

I guess you might mean: (4 2/5) x = 12 1/10 or (22/5) x = 121/10 multiply both sides by 10 44 x = 121 x = 121/44 = 2 3/4 yes

**math - bearings**

or if A to O is east then O to A is west :} That might be where you got stuck.

**math - bearings**

Draw a picture say ?° is 30. then from O to A is 180 + 30 = 210 for any ?° between 0 and 180, add 180 HOWEVER once ?° is greater than 180, then when we add 180 it is bigger than 360 so to get it right you have to back up 180 and use ?° - 180 (or in fact you ...

**Math**

did not realize that 3/3 = 1 ?

**Math**

Multiply both sides of the equation by 3

**math**

pretty nearly two :)

**math - bearings**

You are welcome :) ( I have spent some time at sea :)

**math - bearings**

First of all you do not fly on a "bearing". You fly, or sail, on a "heading". A "bearing" is the direction a lighthouse or whatever is from you. Math texts are totally ignorant of navigation. Anyway, let's do it in conventional x-y axes: 320 ...

**Physic's**

No wings or propeller?

**Physic's**

Force is a vector. Look up what a vector is, or has.

**science**

I believe that the link Ms Sue gave you is fine. However you could try a whole bunch of them and see if they tell you the same thing.

**chemistry electron dots**

H has one electron in the first orbital ring. Unlike the elements further down than H and He, those two elements can only fit 2 electrons in that first shell. So an H atom would have one dot anywhere in the shell. When H forms a Covalent bond there are two dots in that shell, ...

**Math**

2*(3^2)^x - 5*3^x = 12 2*3^x *3^x - 5*3^x = 12 let z = 3^x 2 z^2 -5 z -12 = 0 z = 4 or -3/2 so 3^x = 4 or 3^x = -1.5 now x log 3 = log 4 etc

**Physics**

E = m g h = 1*9.81*.2 = 1.96 yes so (1/2) k x^2 = 1.96 30 x^2 = 3.924 x^2 = .1308 x = 0.36 agreed

**Algebra**

SORRY, FIRST ONE IS INFINITE, SAME SLOPE, SAME INTERCEPT

**Algebra**

y = -1/4x + 1 8y = -2x + 8 Open Infinite None* YES PARALLEL y = 6x + 2 3y = 18x + 12 Open Infinite* None SAME SLOPE BUT DIFFERENT Y AXIS INTERCEPTS, NEVER CROSS -2y = -x + 6 y = 1/2x - 3 Open Infinite SAME SLOPE SAME INTERCEPT, THE SAME EVERYWHERE INFINITE None* y = 5x - 6 3y...

**Physics**

1. yes mgh = 41.2 but only if the ball started at ground level at the end of the rope. 2. v =sqrt(2gh) = 7.67 yes 3. yes, exactly

**math**

area = pi r^2

**physics**

Ke = (1/2) m (10)^2 = 50 m Joules mgh = 50 m - 105 h = 50/g -105/m obviously you have a typo but you should be able to figure it out from there.

**physical science**

The rock will accelerate down at about 9.81 m/s^2 for quite a distance but the guy with the parachute will hit terminal velocity quickly.

**physical science**

Like rock versus parachute :)

**physical science**

As bobpursley pointed out implicitly this question is worded poorly. Ignoring air resistance it falls at about 9.81 m/s^2 acceleration downward, the acceleration of gravity. However after a high speed is reached air resistance does become important depending on the shape and ...

**phsyic's**

Yes, D

**physics**

NO !!!! it is accelerating in direction opposite to x axis, probably slowing down. so: B

**History**

well I do not think B, C or D are reasonable answers so I agree with you.

**Physics question**

Initial momentum of A = .3*4 = 1.2 kg m/s Final momentum of B = .8*1.8 = 1.44 kg m/s change of momentum of B = 1.44-0 = 1.44 so Force on B = change in momentum/time = 1.44 kg m/s / .2 s = 7.2 Newtons Now final velocity of A from conservation of momentum 1.2 = 1.44 + .3 Va so ...

**Math**

yes, 7 * 120 = 840

**Math**

7 hours ( 360 visitors / 3 hours ) = 7 * 120 visitors

**Physics**

Hey what? circumference = 2 pi R :)

**Physics**

Ac = v^2/R m Ac = m v^2/R = 2134 so 905 v^2/R = 2134 but 2 pi R = 3340 so R = 3340/2pi so 905 * 2 * pi * v^2 = 2134 * 3340

**math**

none Associative property: http://www.aaamath.com/pro74b-propertiesmult.html

**Cheater Lambster is banned!**

... but I have only been doing these questions for 65 years and need the practice :)

**physics**

bullet mass = 0.00625 kg initial momentum = 0.00625*365 = 2.28 kg m/s mass after crash = 0.00625+4.50 = 4.506 kg same momentum so v = 2.28/4.506 = 0.506 m/s work done by friction = F d = F * 0.15 m so F = loss of Ke/0.15 = 6.67*loss of Ke but the loss of Ke is all of it (1/2)...

**Maths**

10 cm is 0.10 meter 10 + 0.10 meter/month * 60 months 10 + 6 = 16 meters an - please ! a 600 meter tree?

**physics**

an - What ? ! how? why?

**physics**

90 seconds for 150 m 150/90 = 1.67 m/s now you could do km.hr from that 1.667 m/s * 3600 s/h * 1 km/1000m = 6 km/hour

**phys science**

1. yes 2. No 42.4 3. yes 4.100m/25s = 4 m/s 5. 5+5 = 10 Imagine being on boat and looking at flagpole on land. An - please. It does not help to confuse people.

**math**

-5 -1 3 7 11 for example when x = -1 f(-1) = 4(-1)-1 = -4-1 = -5

**Math**

(n-2) n is (n-2)10 + n = 11 n-20 n (n-2) is 10 n + n-2 = 11 n - 2 sum = 22 n - 22 = 154 so 22 n = 176 n = 8 so 68

**Math**

2y = x - 2 2y =-4x+ 10 different slopes so cross once, agree with you

**Science**

NO!!!!! only those frequencies that correspond to natural frequencies (normal modes) of the pipe would resonate.

**Physics?**

so T is planet period (length of day) Me mass of planet r radius of orbit G is universal gravitational constant r^3 = T^2 G Me /(4 pi^2) r is from center of planet so we need radius of planet for altitude altitude = r - planet radius we do NOT need mass of satellite (but you ...

**Physics?**

Here is the recipe: http://www.dummies.com/education/science/physics/how-to-calculate-the-period-and-orbiting-radius-of-a-geosynchronous-satellite/

**Physics?**

Hey, not around sun!!! Period of planet spin same as period around planet is what synchronous means so it can stay above the same spot. That is obvious. I will have to actually do the rest :)

**Algebra**

total distance covered per second = 7.2 + 8.4 = 15.6 meters/s time = 3120/15.6 seconds to collision That is all you need.

**statistic**

http://davidmlane.com/hyperstat/z_table.html

**for all this stuff**

http://davidmlane.com/hyperstat/z_table.html

**Math**

t * r t * r^2 t = 64 t = 4 * r^2 t so r^2 = 1/4 r = 1/2 t + (1/2)t + (1/4) t = 64 etc

**Math/Physics**

(i) .9 * 1000 = 900 not 9000 are you assuming g = 10 ? If so then indeed weight = 9000 N it is 200 sin 5 I get 157,000 J so you just have typo (ii) agree 20,000 for (iii) total work done by engine = work against gravity + work against friction - loss in Ke = 157,000 + 20,000...

**Physics**

period = 1/f = 1/60,000 = 1.67*10^-5 second goes one wavelength in one period distance = speed * time so wavelength = 340*1.67*10^-5 = .00566 meters = 5.67 millimeters

**algebra**

t = 2.73 for ground time https://www.mathsisfun.com/quadratic-equation-solver.html

**algebra**

we agree about t, but not about h CHECK 16 t^2 - 40 t - 10 = -h 16(1.25)^2 - 40(1.25) - 10 = ? 25 - 50 -10 -35 = -h , you are right I forgot to add 10 on the right

**algebra**

Beat ya :) anyway part 2 16 t^2 - 40 t - 10 = 0 quadratic equation a = 16 b = -40 c = -10

**algebra**

16 t^2 - 40 t - 10 = -h divide by 16 first to get 1 as coef of t^2 t^2 - 2.5 t - .625 = -h/16 t^2 - 2.5 t = -h/16 + .625 half of 2.5 then square get 1.5625, add to both sides t^2 - 2.5 t + 1.5625 =-h/16 + 1.5625 (t-1.25)^2 = -(1/16)(h-25) vertex (top of the parabola) at h = 25...

**algebra**

I assume you do not do calculus so find the vertex of that parabola. That is just like the last one we did :) I will race you.

**science: plz help Mrs. Sue**

agree, web spinning

**Algebra**

x^2 - 6 x + 4 = y subtract 4 from both sides x^2 - 6 x = y-4 square half of 6 which is 3^2=9 add 9 to both sides x^2 - 6 x + 9 = y + 5 factor left, perfect square now (x-3)^2 = y + 5 vertex at (3 , -5)

**Physics**

yes. I thought I answered this earlier.

**physics**

If the wavelength is quadrupled, so is the spacing. Increase wavelength by decreasing frequency.

**Science**

They are great circles with circumferences equal to the circumference of the planet. The prime meridian is zero longitude originally chosen to start counting east and west from Greenwich England. The equator is zero latitude and latitude is measured north and south from the ...

**Math**

covalent bonds are shown as a pair of dots, one from each atom, so the number of bonds a given atom can form is determined by the number of unpaired dots around it. https://opentextbc.ca/introductorychemistry/chapter/covalent-bonds-2/

**Physics**

NO! r = sqrt (1.5^2 + .054^2) r^2 = 2.25+ .003 = 2.253 |F| = k q1 q2 /r^2 Fi = |F| cos angle above -xaxis Fj = |F| sin angle above -x axis that angle is tiny tan angle = .054/1.5 so cos angle is = 1 and sin angle = tan angle = .054/1.5 so Fj = |F| * .054/1.5 = 1/27.7 as Bob ...

**Physics**

You are welcome, good luck. Remember that speedometer and compass.

**Physics**

By the way km/h is a perfectly good way to specify speed. However once you get into calculating accelerations and stuff you will need to convert that to meters/second

**Physics**

the speed is 95 the velocity also has to specify direction Remember, for velocity you need speedometer AND compass. ACCELERATION is rate of Change of Velocity b

**Physics**

You are welcome.

**Physics**

Yes. speedometer the same, compass different.

**Physics**

You are welcome. I believe you get it.

**Physics**

Right! You are on a roll.

**Physics**

Good :) and acceleration can be + or -. Often if negative it is called de-acceleration but not by physicists :)

**Physics**

You are welcome. By the way if you have learned about "centripetal acceleration", that is acceleration with no speed change, just direction.

**Physics**

Speed is a scalar. You an measure it with a speedometer. BUT Velocity is a VECTOR. You need both the speedometer AND a compass. Acceleration is a vector, rate of change of Velocity THEREFORE If speed changes, that is Acceleration ALSO If direction changes, that is acceleration...

**Probability**

Binomial distribution requires replacement, constant probability. See: https://en.wikipedia.org/wiki/Hypergeometric_distribution

**Physics?**

EVEN mixtures?

**math**

.7 x = .2 x + 75 .5 x = 17 x = 34

**That did not work. If you tried to copy and paste, no way**

Can not see the expression

**physics help please**

circumference in light years = 2 pi *3 * 10^4 I think you left the 2 pi out. You need circumference not radius.

**Math**

3n + 1 </= 2n+ 7 n </= 6

**Chemistry**

You are adding H+ ions to neutral water (not really a reaction I think)so yes

**Math**

m/(176-m) = 5/11 solve for m answer is 176-m

**physics help please**

2m/4r^2 1/2 * g 4.9

**Math,Calculus**

sketch graph increasing faster, curving above line, a.

**Physics**

torque = dL/dt = rate of change of angular momentum What else is new? I is moment of inertia of merry-go-round with Lindsey on it. omega = 3.45 L = I omega = 3.45 I that is the initial angular momentum Torque = I d omega/dt or 200 * 2.20 = I d omega/dt if you know I you can ...