Which of the following forces between two objects is proportional to 1/2 for point sources where r is the distance between the objects?

.magnetic force
.gravitational force
.electrostatic force

Why can blue light and yellow light combine to produce white light? question 17 options: they are both primary colors of light. they absorb each other's wavelengths. because blue, yellow, and white are primary colors. they are complementary colors of light.

1. how to locate the image in converging(concave) mirror and diverging (convex) mirror with salt. 2. how to locate the image in a converging (convex) lens and diverging (concave) lens with salt.

How do we measure or think of speed in the united states?