Looks like you aren’t #including RadialForceComponent.h .
Your error is saying that the compiler doesn’t know that “URadialForceComponent” is a type, so it is expecting that string to be an identifier rather than a type, and therefore expecting a ; after the word rather than the * .
Sometimes include files are nested within a module’s folders in order to better organise the code. You’ll need to include a relative path to reference those includes.
You want to use URadialForceComponent::AddCollisionChannelToAffect to do it as it handles the conversion for you, from what I can tell.
By default though, the RadialForceComponent already affects Physics bodies:
// by default we affect all 'dynamic' objects that can currently be affected by forces
AddCollisionChannelToAffect(ECC_Pawn);
AddCollisionChannelToAffect(ECC_PhysicsBody);
AddCollisionChannelToAffect(ECC_Vehicle);
AddCollisionChannelToAffect(ECC_Destructible);