John added 150 grams of salt to 2.5 liters of water. what is the concentration of the salt solutions​

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

Ineed the answer to question 1 , i’m desperate

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?