The table below shows the initial and final masses of a radioactive material in a container. Initial mass (in kilograms)
0.8
Final mass (in kilograms)
0.05
Based on the table, which of these conclusions is correct?
The half life of the material is five years.
The half life of the material is four years.
The material has completed four half lives.
The material has completed five half lives.

Asap , 8th grade science 50 points 1) a 2kg bowling ball sits on top of a building that is 40 m tall. what type of energy does it have? potential energy energy of acceleration kinetic energy chemical energy 2) a 2 kg bowling ball sits on top of a building that is 40 meters tall. how much potential energy does it have? 784 j 80 j 784 n 78.4 j 3) a 4 kg bowling ball rolls at a speed of 5 m/s on the roof of a building that is 30 meters tall. what type of energy does the bowling ball have? both potential and kinetic energy kinetic energy potential energy speed 4) a 4 kg bowling ball rolls at a speed of 5 m/s on the roof of a building that is 30 meters tall. what is its kinetic energy? 50 j 10 j 120 j 1,176 j 5) an 8 kg bowling ball rolls at a speed of 10 m/s on the ground. what type of energy does the bowling ball have? kinetic acceleration potential speed 6) an 8 kg bowling ball rolls at a speed of 10 m/s on the ground. what is its kinetic energy? 40 j 80 j 160 j 400 j 7) a 20 kg child is tossed in the air by her parent. what is her kinetic energy when she is 2 meters off the ground traveling at 5 m/s? 200 j 40 j 100 j 250 j 8) a 1,000 kg car has 50,000 j of kinetic energy. what is its speed? 100 m/s 150 m/s 50 m/s 10 m/s 9) a 200 kg boulder has 39,200 j of gravitational potential energy. what height is it at? 50 m 20 m 150 m 200 m 10) a 1 kg model airplane has 12.5 j of kinetic energy and 98 j of gravitational potential energy. what is its speed? 5 m/s 10 m/s 15 m/s 20 m/s

Iwill give extra points to who gets this right

How many electrons does silver have to give up in order to achieve a sido noble gas electron configuration?