Plz two forces are described below: force 1: the upward force exerted by a chair on us when we sit on the chair force 2: the force which prevents us from slipping when we walk on a smooth surface which statement is true about the forces? both are contact forces. both are non-contact forces. force 1 is a contact force and force 2 is a non-contact force. force 1 is a non-contact force and force 2 is a contact force.