Recent content by Miri

So what do I have to do instead of solving for T?

Turning effects of forces 3 Homework Statement A ruler of an unknown mass is 52.0cm long. To find out its mass, you put a stone of 100g on the ruler 3.0cm from its end and balance the ruler on a sharp edge. The ruler is balanced when the supporting edge is 15.0cm from its end. Calculate the...

Homework Statement A ruler of 0.75N and 52.0cm is supported 1.0cm from each of its two ends. A weight of 1.00N is placed 16.0cm from the left end of the ruler. Determine the forces acting upon the ruler at the two supports. Homework Equations I know that the two forces of the supports...

Can somebody help me? I have my matura exams next week :S Thanks and have a nice weekend

So the volume needed to lift the mass of the balloon shell itself is calculated like this: 7.5*10^-3kg / 1.29kg/m^3=0.006m^3. But what's the point now? Should I calculate 7.5*10^-3kg / 0.18kg/m^3=0.04m^3 and then??

So for T I take 300N*5.00m*sin(53.0°)=1197,95Nm. And as you said, it is +1650Nm when you solve it for T. But now I have two results and the last one is wrong, because I didn't use the formula like in the first one. Can you tell me what to do?

Ok, thanks, I got it...

I don't know what the conditions are. I just know that it has to float. And why do we need a net force? And how would we calculate it? Thx for your patience

So what exactly does this mean? :∑(Cm*m)/∑m, can you give me another formula? When the two forces which are pointing downward are added, then you should get the force which is pointing upward, so the force of your finger. But like I calculated it, it doesn't work...

Is it 300N*2.5m because the force acts in the middle of the beam downwards? So we get 600N*1.50m+300N*2.5m+T=0 so for T we get -1650. Isn't there a mistake? :D And how do I have to use the angle??

When it has 1.2g helium in it. But I don't know how I can calculate this...

So I take for example 100m^3 for the volume of ice. So the mass is (920kg/m^3)*100m^3=92000kg. Then I divide 92000kg by the density of water and I get 92m^3. And then??

So you mean that the force which is pointing downwards (the one from the ruler) has to be equal to zero when you subtracted the force of the rubber? I don't really get what you mean? Can you help me with giving me a formula which relates those two forces so that I can find out the distance...

Homework Statement If ice floats in water, how many percent of it show above the water level? density of water=1000kg/m^3 density of ice=920kg/m^3Homework Equations I really don't know how to start and what I have to do with those densities...just give me a hint. solution would be 8%

Homework Statement The mass of an unfilled balloon is 7.5g. How much helium has to be filled in the balloon to make it float in air? density of helium: 0.18kg/m^3 density of air: 1.29kg/m^3Homework Equations When I calculate the volume like this: (7.5*10^-3kg)/(0.18kg/m^3)=0.041m^3 and than I...