In the manufacture of twist drills, the shank is joined to the body of the drill using
A carpenter needs to drill a hole in the wooden plank using a drilling machine. The depth of the hole to be drilled is 20cm. Find the time required to drill the hole if the machine drills at a speed of 0.3 m/min.
A steel drill making 180 rpm is used to drill a hole in a block of steel. The mass of the steel block and the drill is 180 gm. If the entire mechanical work is used up in producing heat and the rate of rise in temperature of the block and the drill is 0.5∘C/s.The torque required to drive the drill in Nm is
Specific heat of steel =0.1 and J=4.2J/cal. Use: P=τω