A cylidrical drum is pushed by a wooden plank as shown in the fig.The cylinder rolls forward on the ground by a distance l/2 equal to half of the length of the plant.there is no slipping at any point of contact.
Where is the board then?
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A small sphere rolls down without slipping from the top of a track in a vertical plane. The track has an elevated section and a horizontal part is 1.0 m above the ground level and the top of the track is 2.4 m above the ground. Find the distance on the ground with respect to the point B (which is vertically ) below the end of the track as shown in figure. Where the sphere lands. During its flight as a projectile does the sphere continue to rotate about its centre of mass? Explain.

Take four congruent card board colpes of any quadrilateral ABCD , with angles as shown (fig i) Arrange the copies as shown in the figure , where angles angle1,angle2,angle3,angle4 ,meet at a point (fig .ii) What can you say about the sum of the angles angle1,angle2,angle3angle4 ?