Block height
Two identical wooden blocks have a pin put through their centres and are suspended between two glass panes (the pin ends are on the edge of the glass) each. Identical rifles have been pointed upwards toward the blocks. One rifle shoots a block at the centre and the other shoots it closer to an edge. The blocks fly in the air. Which block centre flew higher?
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1 solution
by conservation of linear momentum, them both have same initial velocity of centre of mass (CM). since force is mass*acceleration (of CM), the both blocks accelerate the same, with same initial speed so go the same height. energy conservation is not defied. even though both blocks have same translational kinetic energy, one also has rotational kinetic energy. how is this possible if both systems started with the same Kinetic energy. this is because a lot of the Kinetic energy of the bullet is transformed to internal energy. however, one book gets more energy internal energy (From the KE) than the other, so the other book can have more KE, but less internal energy