Can you tell a real Warhol from a fake? Four art exhibitions to see for free

A show of smart forgeries by Sturtevant will test your critical eye. Elsewhere, there’s a chance to dissect America’s cultural corpse and enter a terrifying immersive painting of Mexico Cady Noland’s US is a violent, celebrity obsessed, consumerist police state. In this small show of big, stark, awkwardly cropped and blurry black and white images and minimal sculptures, the influential…