Homework Help: Help Appreciated

A mass of 10kg lies on a smooth plane which is inclined at xº to the horizontal. The mass is 5m from top measured along the plane. One end of a light inextensible string is attached to the mass. The string passes up the line of greatest slope and over a smooth pulley fixed at the top of the plane. The other end is attached to a freely suspended 15kg mass. This mass is 4m above the floor. The system is released from rest 1 and 3/7 seconds later

Find the volume of xº

~~~~~~~~~~~

The "1 and 3/7 seconds" refers to one second and then 3 sevenths of a second --- i couldn't do a fraction.




Thanks for all you help,

Conor

 

That's all it said, I think -- the system was released

**I'll try to find out if there was anymore

 

Sorry you're rite - there is another bit


A mass of 10kg lies on a smooth plane which is inclined at xº to the horizontal. The mass is 5m from top measured along the plane. One end of a light inextensible string is attached to the mass. The string passes up the line of greatest slope and over a smooth pulley fixed at the top of the plane. The other end is attached to a freely suspended 15kg mass. This mass is 4m above the floor. The system is released from rest and the string first goes slack 1 and 3/7 seconds later

I need to find the angle at which the plane was inclined

The bit in italics is the edited bit

Thanks,
Conor

 

In my first post, i ment to say "size of the angle"

I don't really understand your "theory" of it. I posted this in the general board and it got moved here.

I'm only 13 and our maths teacher set us this challenge - if we can work this out from Monday then we get off homework for the rest of Lent.

If possible, could I have the answer and how to do it.


As I said, this isn't homework

 

OK - I think the answer is 25º

Can someone confirm if this is correct?

 

As said before I have never done a problem of this sort:

I think the answer is one of the following:

a) 25º
b) 8.21º
c) 53º
d) 26.74º


Could anyone tell me the correct answers as I am at a loss and this is very important

 

Yeah - my teacher asked us to find out and try to explain it -- we haven't done anyof this before.

I'm trying to learn but am a bit above my depth.


I will try my best to work it out myself - if someone would kindly explain how to calculate acceleration and how to apply F=MA


**By TheWay, i'm not a 17 yr old posing as a 13yr old so you can do my homework - i said i'll try to work it out if someone told me how to calculate acceleration and how to apply F=MA (If this was really homework, then I would know how to do acceleration and F=MA**

Thanks

Conor

 

We know the weight fell 4m in 1 and 3/7 seconds. From this we can calculate the acceleration, since acceleration is distance travelled (d) divided by time (t) squared. This gives us the following:

4m
_____________
(1 3/7 secs)^2 2.040816 sec^2

=

4m
_____________
(1.42857sec)^2

=

4m
_____________
2.040816 sec^2

approx 1.96m/sec^2 = acceleration=a

Our mass is given at 15 kilograms. Now we can calculate F.

F = ma

F = (15kg)(1.96m/sec^2)

F = 29.4 kg-m/sec^2

This is the force with which the weight fell, aka the force the 15kg weight exerted on the 10kg weight on the smooth plane as they were connected with an inelastic string. Of course the 10kg weight was also acting upon the 15kg weight, slowing its acceleration in comparison to a free falling body, which would have the normal Earth acceleration (aka gravity). Now we need to find out this force in order to find out the angle of the force that resisted the free fall of the 15kg weight.


------------------------------


I've figured this out?? Is it rite??

And now, how do I change the force (29.4N) into the angle?

 

Please, this is really important -- I just need some person to explain to me how to get from N(ewtons) --> º

Thanks

 

OK, well thanks for trying every1

 

Would the upward force be

117.6 N?

 

The correct acceleration?! I'm not sure i understand that bit of it?

do you mean

D = 1/2 a t^2?? If so, then does this make sense as we already have D?

So I need to do

F=ma for the suspended weight and agin for the weight on the plane when I do this I will have two values --> the forces of the two masses.

Then I use these to get the angle? Using what formula?


THanks,
Conor

 

Nah, I'm lost - I don't understand it at all

We'll just do the homework.


Thanks for all your help


Conor