A sample of radioactive material emits 400,000 particle over a period of 20minutes calculate the activity of the source in bacquerel

The dot diagram represents the motion of the motorcycle as it moves from left to right

Ahanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. in this situation, we define its position as x = 0. the object is pulled down an additional 18.0 cm and released from rest to oscillate without friction. what is its position x at a moment 84.4 s later? express your answer in cm.

Abar magnet cut in half will form a total ofpoles. a)fourb)eightc)two