Recent content by konichiwa2x

Hi, I got a doubt while studying rotational mechanics. It is said in my book that when a sphere is purely rolling on a surface, total mechanical energy is conserved even though friction is acting. Isnt friction an external force? How can energy be conserved then?? Another doubt I got is...

I have done exactly that. The linear momentum before impact is mv_{0} and after impact is 2mv where v = v_{0}/2. I did conserve angular momentum (refer my original post). Is there anything wrong in what I did? please help.

Hi, A rod of mass 'm' and length 'l' is lying on a smooth horizontal surface. A particle of mass 'm' is moving with a velocity v_{0} strikes the rod at the centre and sticks to it. What is the velocity of end A after impact? [Solution: \displaystyle \frac{v_{0}}{2}]...

thanks I had earlier done this for case 2: Tcosx=mg. why is that wrong? can't tension be resolved along the vertical? can you please explain that? yup, tension before the cord is cut. Otherwise, the tensions are same right! so T1/T2 = 1.. but what is causing it to accelerate in the...

Hi, Can someone please explain how to do this problem? I really don't understand. A ball is held at rest in position A as shown in the figure by 2 light cords. The horizontal cord is cut and the ball swings as a pendulum. What is the ratio of the tensions in the supporting cord, in position...

Hi, Can someone please expain how to do this problem? I have spent about an hour today on this can and still can't figure it out. In the arrangement shown in the figure, a wedge of mass m_{3} = 3.45kg is placed on a smooth horizontal surface. A small and light pulley is connected on its...

ok mgh = \frac{mv^2}{2} + \frac{I\omega^2}{2} solving, velocity = \frac{v}{\sqrt{2}} correct? thanks for your help.

ok here goes let F1 and F2 be the forces on the bar due to the ground and the man respectively. Let B be the centre of the bar. A and C are the points on the ground and on the man respectively. so W = F1 + F2 Net torque must be 0. F1 x AB = F2 x BC F1.AB.sin(a) =...

ok thanks a lot!:smile:

A body of mass 'm' slides down an incline and reaches the bottom with a velocity 'v'. If the same mass were in the form of a ring which rolls down the incline, what would have been the velcity of the ring? (A)v (B)\sqrt{2}v (C)\frac{1}{\sqrt{2}}v (D)\frac{\sqrt{2}}{\sqrt{5}}v How...

If the beam is horizontal when both the pans are empty, doesn't that mean both the pans have equal mass? Anway, is this what you meant? m1 = km2 m1 + x = m2 + 8 m2 + 18 = m2 + x solving, x = 13? Is this correct? My book says the correct answer is 12gm..

I know torque = Force x distance also torque = moment of intertia . angular acceleration. but I still don't understand how to do this problem using this.

Hi, A body weighs 8gm when placed in one pan and 18gm when placed on the other pan of a false balkance. If the beam is horizontal when both the pans are empty, then what is the true weight of the body? How do I do this? Please help.

allright that makes sense. thanks a lot for your help

ok I get your point. But then, why does the cylinder roll up the plane in the first place??