How do you give Objects in your scene Weight and Player can push them?

Just lay a bunch of objects like boxes , rocks etc. The heaveir objects like cars, can’t move but i want my character to be able to PUSH other objects.

Like if there’s a heavy big box and the character(I"m doing an FPS)
walks through it, the character should not be able to pass through, instead he will push it but the box will give out force and the speed of the character walking will slow down.

that’s what i want to do. even if it wasn’t an FPS sstyle game.

Turn the objects you want to be pushed around into rigid bodies.