Aradioactive sample of a pure element produces 30240 decays per minute at one point in an experiment and 101.95 minutes later, produces 945 decays per minute. what is the half-life? (ii) what is the decay constant? (iii) what is the mean lifetime of the element? (b) what fraction of a sample of sodium-22 is left after 6.505 yr. (the half-life of sodium-22 is 2.602 yr.) (c) what period of time is required for a sample of radioactive carbon-14 to lose 66.667% of its activity? (the half-life of carbon-14 is 5730 yr)

Using proper grammar, spelling, and punctuation, write at least one 5 sentence paragraph describing 3 ways we use the elements of the electromagnetic spectrum (ems) in our everyday lives.

Review multiple-concept example 7 in this chapter as an aid in solving this problem. in a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. in one instance, the radius of the circle is 0.626 m. at one point on this circle, the ball has an angular acceleration of 66.1 rad/s2 and an angular speed of 12.6 rad/s. (a) find the magnitude of the total acceleration (centripetal plus tangential) of the ball. (b) determine the angle of the total acceleration relative to the radial direction.

Adistance-time graph indicates than an object moves 100 m in 4 s and then remains at rest for 6 s. what is the average speed of the object?