We will have the following:
1. In the first case, we will calculate the normal force:
Then, we will have that the fricion coefficient will be:
So the magnitude of the friccional force when applied horizontally will be of 30.0N.
2. And the magnitude when applied horizontal but the block is on an inclined surface of 60°, we will have that:
So, the friction force when the force is applied, is 15N.