I'm going to assume this is over a horizontal distance. You know from Newton's Laws that F=ma --> a = F/m. You also know from your equations of linear motion that v^2=v0^2+2ad. Combining these two equations gives you v^2=v0^2+2(F/m)d. We can plug in the given values to get v^2=0^2+2(20/3)0.25. Solving for v we get v=1.82 m/s!
The half life of Carbon-14 is 5730 years, how many years would it take for 7/8 of the original amount to decay?
<span>Can somebody please help with this problem. I *think* I understand the basics of what a half life is. If I learned correctly, its the amount it takes for half of a sample to decay. It should also happen exponentially, 1/2 remaining after one half life, 1/4 after the second, 1/16 after the third etc. I'm still a little shaky though. Could somebody please clarify what exactly a half life is and how it can be determined (i.e. how to find the time it would take for 7/8 to decay) </span>
Answer:
15 meters
Explanation:
The inicial energy of the ball is just potencial energy, and its value is:
E = m * g * h = m * g * 20,
where m is the ball mass, and g is the value of gravity.
In the moment that the ball strickes the ground, all potencial energy transformed into kinetic energy, and 25% of this energy is lost, so the total energy at this moment will be:
E' = 0.75 * E = 0.75 * m * g * 20 = 15*m*g
This kinetic energy will make the ball goes up again, and at the maximum height, all kinetic energy is transformed back into potencial energy.
So, as the mass and the gravity are constants, we can calculate the height the ball will reach:
E' = m*g*h = 15*m*g -> h = 15 meters
Answer:
there are 7 significant figures
Explanation:
15.33879+15.555
=30.89379
there are 7 significant figures
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