What is one common source of background radiation?

Explanation:

Background radiation is a measure of the ionizing radiation present in the environment. The most common source of this is cosmic radiation, which is formed by high energy sub-particles, which almost at light speed. All these particles come from the Sun and other stars, even from other galaxies.

In addition, another common source is the environmental radioactivity, which is produced by radioactive materials, some naturals, other by humans.

Therefore, the answer that best fit is cosmic radiation.

conduction, convection, radiation

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft