Answer:
1,3
Explanation:
As the acceleration is -10m/s^2 , that means deceleration is occurring. That means, the object is slowing down.
v=u-at
or, 0=80-10t
or, t=8 seconds
So, the object will stop in 8 seconds.
So, the correct answers are 1 and 3.
Hope, this helps you.
Answer:
The SI unit for electric chargeis the C (which is the abbreviation of Coulomb}
Explanation:
The SI unit for electric chargeis the Coulomb. The letter used is the C.
1 C = 1 As
On sources it says it would just be the super giant star
Stairs don't have any power at all. All the energy used to climb them
has to come from your muscles.
An elevator gets its power from the electric motors that lift it. All YOU
have to do is stand there and look around.
All of this is a big part of the reason why elevators have become so
popular, and why no buildings with more than a few floors were built
before elevators were invented.
Answer:
8. 2.75·10^-4 s^-1
9. No, too much of the carbon-14 would have decayed for radiation to be detected.
Explanation:
8. The half-life of 42 minutes is 2520 seconds, so you have ...
1/2 = e^(-λt) = e^(-(2520 s)λ)
ln(1/2) = -(2520 s)λ
-ln(1/2)/(2520 s) = λ ≈ 2.75×10^-4 s^-1
___
9. Reference material on carbon-14 dating suggests the method is not useful for time periods greater than about 50,000 years. The half-life of C-14 is about 5730 years, so at 65 million years, about ...
6.5·10^7/5.73·10^3 ≈ 11344
half-lives will have passed. Whatever carbon 14 may have existed at the time will have decayed completely to nothing after that many half-lives.
