Answer:
10⁴¹ s quark top lives have been in the history of the universe.
Explanation:
You need to determine how many quark top lives there have been in the history of the universe, that is, what is the age of the universe divided by the lifetime of a top quark. Expressed in a formula, this is:
Yo know that the "Age of the universe" is 100,000,000,000,000,000 which can also be expressed as 10¹⁷ s
.
You also know that the "Lifetime of a top quark" is 0.000000000000000000000001 which can also be expressed as 10⁻²⁴ s.
Then 
Recalling that the result of dividing two powers of the same base is another power with the same base where the exponent is the subtraction of the initial exponents, it is possible to calculate this division as follows:
<u><em>t=10⁴¹ s</em></u>
So <u><em>10⁴¹ s quark top lives have been in the history of the universe.</em></u>
<span>So we want to know which statement is true for the body of mass m=2000kg that is lifted to a height of h=15m in t=15 s. Lets calculate each of the following: Gravity force on the body is F=m*g=2000*9.81=19620 N so a is FALSE. Potential energy of the body when it is lifted to the height of 15 m is Ep=m*g*h=2000*9.81*15=294300 J so b is FALSE. Work to lift the body is: W=Fg*h=2000*9.81*15= Ep=294300 J so c is FALSE. Power P=W/t=294300/15=19620 W So d is TRUE. </span>
C. A mechanical wave generally travels faster in gases than liquids.
Answer: D. An action-reaction force pair
Explanation: When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body. There are two forces resulting from this interaction - a force on the chair and a force on your body. Another example would be a person pushing against a wall (action force), and the wall exerts an equal and opposite force against the person.
Answer:
Please refer to the figure.
Explanation:
The magnitude of the magnetic field can be found by Biot-Savart Law. We should divide the loop into four components. Each component has a similar solution but their directions are quite different.
The directions can be found by right-hand rule. Point your index finger into the direction of current, point your middle finger towards the target point (0,0,a). Your thumb will show you the direction of magnetic field.
