Applying force to the player

Hey, Looking for some assistance with applying force to a player, I want to make it so that when a certain item is held and the player looks to a block and right clicks they are knocked

backwards in the opposite direction by some fair degree.

I imagine this will need to be done in code and that's fine, just need a baseline to work with as it's my first time with the software and coding of it all.

Would appreciate any help anyone could give. Thanks.