As you stop your car at a traffic light, a pebble becomes wedged between the tire tread. The distance the pebble is from the pavement will vary sinusoidally with time. The equation that represents this is y=-12cos1/12x+12, where x represents the time driven in seconds and y represents the distance the pebble is from the pavement in inches. What is the first time the pebble is 11 inches from the ground?