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.
Electro waves in a vacuum air is deals with this and electricity when the air and the electricity it makes electro magnets.
(a) The angular acceleration of the wheel is given by

where

and

are the initial and final angular speed of the wheel, and t the time.
In our problem, the initial angular speed is zero (the wheel starts from rest), so the angular acceleration is

(b) The wheel is moving by uniformly rotational accelerated motion, so the angle it covered after a time t is given by

where

is the initial angular speed. So, the angle covered after a time t=3.07 s is
Answer:
Torque on the rocket will be 1.11475 N -m
Explanation:
We have given that muscles generate a force of 45.5 N
So force F = 45.5 N
This force acts on the is acting on the effective lever arm of 2.45 cm
So length of the lever arm d = 2.45 cm = 0.0245 m
We have to find torque
We know that torque is given by 
So torque on the rocket will be 1.11475 N -m
The mass of the iceberg is 71.9 kg
Explanation:
The amount of thermal energy needed to completely melt a substance at its melting point is given by

where
is the latent heat of fusion
m is the mass of the substance
In this problem, we have a block of ice at its melting point (zero degrees). The amount of heat given to the block is

And the latent heat of fusion of ice is

So, we can re-arrange the equation to find m, the amount of ice that will melt:

Learn more about specific heat:
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