Answer:
The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).
Explanation:
The gravitational force is the force of mutual attraction that two objects with mass experience.
The Law of Universal Gravitation enunciated by Newton says that every material particle attracts any other material particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance that separates them. Mathematically this is expressed as:

where m1 and m2 are the masses of the objects, r the distance between them and G a universal constant that receives the name of constant of gravitation.
If the distance between two particles is reduced by half, then, where F' is the new value of the gravitational force:




F'=4*F
<u><em>
The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).</em></u>
The equation
(option 3) represents the horizontal momentum of a 15 kg lab cart moving with a constant velocity, v, and that continues moving after a 2 kg object is dropped into it.
The horizontal momentum is given by:


Where:
- m₁: is the mass of the lab cart = 15 kg
- m₂: is the <em>mass </em>of the object dropped = 2 kg
: is the initial velocity of the<em> lab cart </em>
: is the <em>initial velocit</em>y of the <em>object </em>= 0 (it is dropped)
: is the final velocity of the<em> lab cart </em>
: is the <em>final velocity</em> of the <em>object </em>
Then, the horizontal momentum is:

When the object is dropped into the lab cart, the final velocity of the lab cart and the object <u>will be the same</u>, so:

Therefore, the equation
represents the horizontal momentum (option 3).
Learn more about linear momentum here:
I hope it helps you!
All, or almost all, warm-blooded creatures get rid of excess heat by evaporating moisture from their bodies. It's a great system, because evaporation takes a lot of heat. That's the reason people perspire when we're active and build up a lot of heat inside. The evaporation of sweat from our skin carries away heat with it.
Dogs do not sweat on their skin. The only place they can evaporate moisture is through their mouth. Panting speeds up the evaporation by blowing air across the moisture.
Answer:
B) Power
Explanation:
The power is defined by the following equation:
P = W / t
where:
W = work = Force * Distance = [Newton] * [meter]
t = time = seconds
The units for work are give en Newton per second, which is equal to Joules
And for power the unit used commonly is Watts, therefore:
Watts = (Joule/second)
A heat engine is a device that uses heat to produce useful work.