What is the name of the device that sense the current flowing

Ampermeter

Explanation:

An ampermeter is a device that allows measuring an electron flow through a wire.

His main operation principle is to generate a magnetic field on a coil, which then is converted to an electric potential or voltage to be compared with a voltage reference, producing there a measurable value.

There are 2 types of ampermeters one is the standard form, which is a clamp that surrounds a wire and measures without changing/touching the circuit. The other one uses to terminals and it's required to open the circuit and make the current flow go through the ampermeter.

need to see circuit to get time constant

massxgravity x heght=weightxheight= pe

4900=490xh

h=10