Answer:
U = -3978.8 J
Explanation:
The work of the gravitational force U just depends of the heigth and is calculated as:
U = -mgh
Where m is the mass, g is the gravitational acceleration and h the alture.
for calculate the alture we will use the following equation:
h = L-Lcos(θ)
Where L is the large of the rope and θ is the angle.
Replacing data:
h = 12.2-12.2cos(58.4)
h = 5.8 m
Finally U is equal to:
U = -70(9.8)(5.8)
U = -3,978.8 J
question one b
question 2 i think a
3 d
4 c
5 not sure but wanting to say d
6 letter b
7 not sure
8 idk
9 i have no idea
Answer:
a) 0.0288 grams
b) ![2.6*10^{-10} J/kg](https://tex.z-dn.net/?f=2.6%2A10%5E%7B-10%7D%20J%2Fkg)
Explanation:
Given that:
A typical human body contains about 3.0 grams of Potassium per kilogram of body mass
The abundance for the three isotopes are:
Potassium-39, Potassium-40, and Potassium-41 with abundances are 93.26%, 0.012% and 6.728% respectively.
a)
Thus; a person with a mass of 80 kg will posses = 80 × 3 = 240 grams of potassium.
However, the amount of potassium that is present in such person is :
0.012% × 240 grams
= 0.012/100 × 240 grams
= 0.0288 grams
b)
the effective dose (in Sieverts) per year due to Potassium-40 in an 80- kg body is calculate as follows:
First the Dose in (Gy) = ![\frac{energy \ absorbed }{mass \ of \ the \ body}](https://tex.z-dn.net/?f=%5Cfrac%7Benergy%20%5C%20absorbed%20%7D%7Bmass%20%5C%20of%20%5C%20the%20%5C%20body%7D)
= ![\frac{1.10*10^6*1.6*10^{-14}}{80}](https://tex.z-dn.net/?f=%5Cfrac%7B1.10%2A10%5E6%2A1.6%2A10%5E%7B-14%7D%7D%7B80%7D)
= ![2.2*10^{-10} \ J/kg](https://tex.z-dn.net/?f=2.2%2A10%5E%7B-10%7D%20%5C%20J%2Fkg)
Effective dose (Sv) = RBE × Dose in Gy
Effective dose (Sv) = ![1.2 *2.2*10^{-10} \ J/kg](https://tex.z-dn.net/?f=1.2%20%20%2A2.2%2A10%5E%7B-10%7D%20%5C%20J%2Fkg)
Effective dose (Sv) = ![2.6*10^{-10} J/kg](https://tex.z-dn.net/?f=2.6%2A10%5E%7B-10%7D%20J%2Fkg)
Answer: The speed will be 30 m/s .
Explanation:
Given: Initial velocity of the car: u = 0 m/s
Constant Acceleration: a = 5 m/s²
Time: t= 6 seconds
To find: Final velocity(v)
Formula: v = u+at
Substitute values in the formula, we get
v= 0+(5)(6) m/s
⇒ v= 30 m/s
i.e. Final velocity = 30 m/s
Hence, the speed will be 30 m/s .