Question

A pebble of mass 0.05kg is thrown vertically upward. Give the direction and magnitude of the net force on the pebble during its upward motion

Answer 1

When the pebble is thrown vertically upwards, the only force it experiences is downward gravitational force.

Ofcourse other forces such as drag, air currents are there, but they are neglect able.

Net force will be Mg, that is

$0.05 \times 9.8$

That is 0.49 N. It's direction is downwards.