If a child hits a parked car with their bicycle, the liability will depend on the specific circumstances and the laws in your jurisdiction. In general, children under a certain age are not considered to be legally responsible for their actions, so they may not be held liable for the damage to the car. However, if the child is old enough to be considered responsible for their actions, they may be liable for the damage. Additionally, if the child's parents or guardians were negligent in supervising the child, they may also be held liable for the damage.
It is important to note that the laws regarding liability for children who cause damage to property vary from jurisdiction to jurisdiction. Therefore, it is important to consult with a local attorney to determine the specific laws and regulations that apply in your case.