How do you inspect and test an abrasive wheel?

An abrasive wheel is a machine that can cast materials such as granite or limestone. To inspect and test an abrasive wheel it's wanted to hold the wheel in the air with one finger in the shaft space, then tap the side of the wheel with the handle of a screwdriver about one or two inches from the exposed edge. Turn the wheel 45 degrees and replicate this process until the wheel has been eliminated in four spots that are 45 degrees one from the other. If the tapping takes a definite ringing noise then the wheel is generous. If the sound that it delivers is a hollow and dead sound then the wheel is bad.

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it