A1.0-kg block is pushed up a rough 22° inclined plane by a force of 7.0 n acting parallel to the incline. the acceleration of the block is 1.4 m/s2 up the incline. determine the magnitude of the force of friction acting on the block.

The answer is 1.9 N done with the following equation:
7-mgSinG-f=ma
f=7-mgSinG-ma
=1.92N

It's easiest if you draw out the diagram of the problem first and fill in all the known and missing parts to come up with the equation that you will need to use to solve the problem. In this case we know the angle, weight, force, and acceleration and must find the magnitude acting upon the block.