a cube has a rib ABCD.EFGH, the midle point P on BF so that BP = PF,
and the midle point Q on FG so that FQ = QG
how long projection point C to APQH field ?
Metal pellets of mass 0.1 kg are fired into an iron plate of large mass m
and specific heat capacity c at a temperature of 15°C . 25% of the kinetic
energy of the pellets is converted thermal energy and the plate temperature
rises to 16°C. The average speed of the pellets before hitting the plate was ?