Try this solution, answers are marked with red colour.
ur answer is A or also known as
When you push a child on a swing, you are doing work on the child because you are pushing against the force of gravity
hope this helps :)
Answer:
Explanation:
Solution is in the picture attached
The half life is 30 minutes.
30 mins- 1/2 left
60 mins- 1/4 left
90 mins- 1/8 left
120 mins- 1/16 left
120 mins= 2 hours