Wednesday

March 4, 2015

March 4, 2015

Total # Posts: 40

**friction**

A 40 kg slab rests on a friction less floor.a 10 kg block rests on top of the slab.the coefficient kinetic friction between the block and the slab is 0.40.a horizontal force of 100N is applied on the 10 kg block.find the resulting acceleration of the slab.
*September 28, 2014*

**math.**

Distance covered in 4 hrs=4y Return distance=2x4y=8y and speed=5y Hence time of return trip=8y/5y=1.6hr Halt=1hr Total time=4+1+1.6=6.6hrs
*July 17, 2013*

**math**

Relative velocity=45+55=100mph Time taken to cover the total distance=150/100=1.5 hr i.e. 1hr 30min Meeting time is 2:15+1:30=3:45pm
*July 17, 2013*

**math**

1hr10min=1+10/60=1+1/6=7/6hr Distance=48x7/6=56miles
*July 17, 2013*

**math**

Total money=x. Spent in I store=(x/2)+20 Remaining amt=x-[(x/2)+20]=(x/2)-20 Spent in II store=1/2[(x/2)-20]+20 =(x/4)+10 Total expenditure is x x=(x/2)+20+(x/4)+10 Or x=(3x/4)+30 Or x-3x/4=30 x/4=30 or x=120. Check: Spent in I store =60+20=80. Remaining=40. Spent in II store=...
*July 17, 2013*

**algebra**

Please read second expression as 3(8x^2+14x+5)
*July 17, 2013*

**algebra**

24x^2+42x+15=3(8x^2+14+5) =3(8x^2+10x+4x+5) 3[2x(4x+5)+1(4x+5)] =3(4x+5)(2x+1)
*July 17, 2013*

**algebra**

Sorry. I wanted it to be (1-6x)^3-3x6x(1-6x)
*July 17, 2013*

**algebra**

-216x^3+1=1^3-(6x)^3 =(1-x)^3-3x(1-x)
*July 17, 2013*

**math**

Time for going upwqards=7/2=3.5 hrs Time for coming back=7/3.5=2 hrs Total 3.5+2=5.5 i.e. 5 1/2 hrs
*July 16, 2013*

**math**

In 1.75 hrs it fills 100% In 1 hr it will fill 100/1.75=57.14%
*July 16, 2013*

**math**

(-16)^-2/3=- 1/(16)^2/3=-1/(16^2)^1/3 =-1/256^1/3=-1/6.35=-0.157
*July 16, 2013*

**algebra**

(300)^1/2 /6^1/2=(300/6)^1/2 =50^1/2=7.07
*July 16, 2013*

**Math Ratios**

Force is inversely proportional to square of distance between bodies, hence F/3.75x10^-5=18^2/52^2 F=(18^2x3.75x10^-5)/52^2 =0.46x10^-5 dynes
*July 16, 2013*

**math**

PS: There is slight typo. Please readt first line as 'Kath is' and third line as 2x+10.
*July 15, 2013*

**math**

If the number is x, then 3x-8 is=or greater than 2x. Agnus has x bones and Ignatz has x+5. Then x+x+5=27 or 2x=27-5=22 Or x=11. Ignatz has 11+5=16. Kathy mis x and John is x+10 Then x+x+10 is greater than 60 Or 2x+10is greater than 60 Or 2x 10 is greater than 50 Or x is ...
*July 15, 2013*

**MATH**

If cos^-1x=A then cosA=x and if (cosx)^-1=A then A=1/cosx
*July 15, 2013*

**math**

If house costs x and lot costs y then x+y=86000, and x=6y+2000 or x-6y=2000. Subtracting second eq. from first we get 6y+y=86000-2000 or 7y=84000 or y=12000. Thus lot costs $12000 House costs 86000-12000=$74000.
*July 15, 2013*

**algebra**

No. of $5=bills a, $10 bill=b and $20 bill=c Then a+b+c=35 5a+10b+20c=370, and b+c=a+7. Substituting value of b+c in first eq., a+(a+7)=35 or 2a=28 or a=14 and b+c=35-14=21. Substituting value of a in second eq., 14x5+10b+20c=370 or 10b+20c=370-70 Or 10b+20c=300 or b+2c=30 ...
*July 15, 2013*

**Math**

PS: s=11.47 which has appeared as 121.47 at one place in 4th line.
*July 15, 2013*

**Math**

v=u-gt or 0=15-9.81t since final velocity is 0 and ball is going against gravity. Thus t=1.53 sec. s=ut-.5gt^2=15-.5x9.81x(1.53)^2 s=22.95-11.48=121.47 which is the height the ball will go. From there it falls freely for a height of 11.47+1=12.47 ft. s=0xt+.5x9.81xt^2 or t=(12...
*July 15, 2013*

**algebra**

9.95x+11.5y=305.05 x+y=29 9.95x+9.95y=29*9.95 Or (11.50-9.95)y=305.05-288.55 1.55y=16.5 y=16.5/1.55=10.6, say 11 yellow shirts 29-11=18 white shirts 11*11.5+18*9.95=305.6 OK.
*July 15, 2013*

**algebra**

Lemon juice=x Oil=2x x+2x=3x=36
*July 15, 2013*

**maths**

If one train has a velocity of V km/h, the other one will have velocity V+5 km/h approaching the first train. Therefore Relative velocity will be V+V+5=2V+5 km/h. Distance travelled by them in 2 hrs is 340-30=310km which is =2(2V+5) Thus 4V+10=310 or 4V=300 hence V=75km/h and ...
*July 15, 2013*

**physics**

v=u+ft or 30=10+2t t=(30-20)/2=10 secs.
*July 15, 2013*

**Algebra**

Yes please. 10 cubed is 1000 and cuberoot of q^36=q^(36/3)=q^12
*July 15, 2013*

**algebra**

Please see your third line: It should be 4y-3y=20-5 or y=15, by subtracting first equation from second. Now x+3*15=5 Or x=5-45=-40. Check:-40+4*15=20 by putting values in second equation. This -40=15-60=-40 OK.
*July 15, 2013*

**math**

Let present age of Kristen be x and of Daniel be y.Then after 1 year, x+1=4(y+1)or x-4y=3.....Eq.1 After 10 yrs from then, ages will be (x+1)+10=2[(y+1)+10] Or x+11=2y+22 Or x-2y=11 .....Eq.2. Subtract eq. 1 from eq.2 and solve. We get y=4 and x=19. Check: After 1 year Kristen...
*July 14, 2013*

**physics**

v=u+at or 220/4=200/2+a*1 55=50+a or a=5m/s^2 Again, v=55+5*1=60m/sec at the start of 7th second.
*July 14, 2013*

**math**

Let the integers be x and x/4.Then x/4+12=x-3 or x+48=4x-12 by multiplying both sides by 4. Or -3x=-20-48 or x=20 which is the larger integer. Smaller one is then 20/4=5. Check:5+12=17=20-3 OK.
*July 14, 2013*

**math**

Let it be x yrs ago, when Lisa was 15-x and her father was 40-x. Then- 40-x=6(15-x) or 40-x=90-6x Or 6x-x=90-40 or 5x=50 thus x=5. Let Bob be x yrs and Joel be 3x. Then (x+7)+(3x+7)=58 or 4x+14=85 Or 4x=44 hence x=11. Thus Bob is 11 and Joel is 33. After 7 yrs Bob willbe 18 ...
*July 14, 2013*

**maths**

Prove that max & min values of asinx+bcosx are = +/- (a^2+b^2)^1/2
*July 12, 2013*

**Geometry**

Square has all sides equal hence 2x-5=x+8 or 2x-x=8+5 (by subtracting x and adding 5 on both sides) Thus x=13 inches. Check: 2x13-5=8+13 or 26-5=21.
*July 12, 2013*

**physics**

Weight is mass m times acceleration due to gravity g, which is given by g=GMm/R^2 where M and R are mass & radius of Earth and G is Universal Gravitational Constant. For new planet, g`=G(0.1Mm/(R/2)^2 =0.1GMm/R^2/4 =GMm(0.1x4)/R^2=0.4GMm/R^2 Hence g/g`=0.4, which means the ...
*July 12, 2013*

**maths**

Find max and min values of y=sinx sin2x
*July 11, 2013*

**physics**

Components of a force P due North-West acting at an angle A from North will be PcosA and PsinA in North and West directions respectively and should be equal in magnitude to the force acting on the object. Thus PcosA=83.4 and PsinA=47.2. Therefore tanA=47.2/83.4 =0.566 and A=...
*June 30, 2013*

**physics**

Heat released by 0.5 kg silver=heat gained by 1 kg water upto final temp T. Or 0.5(2.4x100)(150-T)=1(4.18x1000)(T-5) Or 1.2(150-T)=41.8(T-5) Or 180-1.2T=41.8T-209 Or 43T=389 Or T=9.05 deg Celsius
*January 12, 2013*

**Physics**

t^2=2x3.14x0.47/a Or, a=6.28x0.47/1.43^2=0.43 m/sec^2
*November 3, 2012*

**math**

. A boat is travelling on a bearing of 25° east of north at a speed of 5 knots (a knot is 1.852 km/h). After travelling for 3 hours, the boat heading is changed to 180° and it travels for a further 2 hours at 5 knots. What is the boat’s bearing from its original ...
*October 18, 2011*

**physics**

what happend 2 ur mobile? i was trying 2 call u but i got this msg: welcome 2 D jungle network,D monkey u r tring 2 call is on tree plz try later.
*July 17, 2008*

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