All Answers 358115 Answers

I am not angry Rosala.  It was a joke. I didn't mean to upset you.  Sorry.

But (-9)+(-8) = -9-8 = -17 

Thanks Heureka.    

I will check it out   

17. The red ball will bounce back after collision and move in the same direction the yellow ball went previously. This means the speed must be negative and only one of the answers is negative so answer d seems logical.

=>(Red)     (Yellow)<=

(Red)(Yellow)

(Red)<=  =>(Yellow)

The red ball will move in the opposite direction so negative speed. So answer D should be correct.

24.

E(potential)=m*g*h=m*9.81*(5-2)=m*29.43

E(kinetic)=1/2*m*v^2

E(kinetic)=E(potential)

1/2*m*v^2=m*29.43

v^2=29.43*2=58.86

v=58.86^(1/2)=7.67

The correct answer is C

I am sorry 315, I have not had a chance to look at them and I don't know how many I could answer anyway.

I will add this thread to the other one and high light them as unanswered.

Alan may have missed it and David has not been about for a while.

Chris may have a go at some when he is back on.

Anyway that is all I can do for you at the moment. sorry.

I'm lost, which bit didn't you understand?

are the pictures still unclear 

Thanks for sharing this site with us.

I haven't had a chance to look at it properly yet but it will get a mention in my next "wrap" so others can also check it out.  

I put out a wrap most days.

Thank you soooo much Melody, can you please explain the last part, finding "a2 didnt get it :/

Use the site calc on the home page.

(0.88*50)^6

How many 5s are there in 100?

How many 5c peices make up a $1 (which is 100 cents)

The question. A certain radioactive substance has a half-life of 30,17 years. in the model you can calculate the remaining substance, as a function of time: N (t) = 17.5*a^t, where N (t) is remaining substance (measured in grams) and "t" is time (measured in years)...

When t=0

N(0)=17.5*a^0 = 17.5  So the original amount of substance is 17.5 grams.

The half life is the amount of time it takes for the original to decrease by half so N(30.17)=17.5/2=8.75grams

$$8.75=17.5*a^{30.17}$$

Divide both sides by 17.5 and you get

$$0.5=a^{30.17}$$

Raise both sides to the power of (1/30.17) and you will have the value of a    

Hi BlindxD

I don't think that I am understanding this question properly.

24% did not answer the question at all

The number who answered it correctly is 1.5 times this which is 36% of the total students.

That makes a total of 60% the rest DID attempt the question but got it wrong.

That means that 40% of all the students is 10 students.

Now if 40% of All = 10 then

All=10*100/40 = 25 student

I thought that there was a problem but it was only in my imagination.  This is fine. 

Find "a" for the substance ??

The question. A certain radioactive substance has a half-life of 30,17 years. in the model you can calculate the remaining substance, as a function of time: N (t) = 17.5*a^t, where N (t) is remaining substance (measured in grams) and "t" is time (measured in years)...

The 30.17 years has no relevance unless you are given the N when t=30.17

don't you have the original question in front of you?

Do you want to make a the subject?

maybe i need to change the formular so it will say a=.. or something?

Yes I understand that but I need to know how much is left after 30.17 years in order to find a.

(or after any specific number of years for that matter)

It is not going to be the amount left either - the amount is growing all the time.

Perhaps you have an entire question that you can type in?

"N" is the amount of mass left after certain years, measured in grams

$$N(30.17)=17.5*a^{30.17}$$

you have got 2 unknowns here. N(t) and a

You need to know what N(30.17 ) is before you can find a.

Beats me, did you look under your bed?

"PLZ ANSWER NOW" does not sound very polite!

If you have a cube with a volume of  343/1000cubic feet then each side will be     $$\frac{\sqrt[3]{343}}{\sqrt[3]{1000}} \;feet$$

You can do the calculation.

How to multiply what?

Hi Rosala,

The lowest common multiple of 2 and 5 is 10.  So I think the cube would have to have side length 10cm

If you let the front of the little rectangular prism (you call that a cuboid) be 2cm by 5cm

2*5=10 and 5*2=10 so there will be 5*2=10 0f these making up the front of the cube

The little boxes go back 5cm so you will need to double this to get 10 cm.

So the answer must be 5*2*2=20 little cuboids.

I'll see if I can draw it.

Mmm lets see.  I don't know if you have been given a technique Rosala.

$$\sqrt[3]{4913}$$

What digit cubed ends in 3 . 

1^3=1, 2^3=8, 3^3=27, 4^3=64, 5^3 no, 6^3 no, 7^3 yes no 8^3no 9^3=no

I know the number ends in 7 because 

7*7=47 9*7=63  No other's will end in 3

10^3=1000 too small

20^3=2^3*10^3=8000 too big

So the number has to be between 10 and 20 and end in 7

So the number has to be 17