1.) What is the half-life of a 100.0 g sample of nitrogen-16 that decays to 12.5 grams in 21.6 seconds?

From 0 to 5 seconds john pushed a box 5 meters. from 5 to 10 seconds, paul pushed the same box another 5 meters. who did more work? a. john b. paul c. john and paul did the same amount of work.

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? how far will the football travel before it lands?

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.