In a position-time graph what does it mean when you return to 0? asap !

What is the frequency of a light wave with a wavelength of 620nm

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

The weights of bags filled by a machine are normally distributed with a standard deviation of 0.05 kilograms and a mean that can be set by the operator. at what level should the mean weight be set if it required that only 1% of the bags weigh less than 9.5 kilograms? round the answer to 2 decimal places.