The answer is D because when the positive charged side touches the negative charged side it nullifys part of the positively charged side, basically subtraction from my understanding?
Leaning against a brick wall.
All the others use scientific forces of work.
-Steel jelly.
Answer:at 21.6 min they were separated by 12 km
Explanation:
We can consider the next diagram
B2------15km/h------->Dock
|
|
B1 at 20km/h
|
|
V
So by the time B1 leaves, being B2 traveling at constant 15km/h and getting to the dock one hour later means it was at 15km from the dock, the other boat, B1 is at a distance at a given time, considering constant speed of 20km/h*t going south, where t is in hours, meanwhile from the dock the B2 is at a distance of (15km-15km/h*t), t=0, when it is 8pm.
Then we have a right triangle and the distance from boat B1 to boat B2, can be measured as the square root of (15-15*t)^2 +(20*t)^2. We are looking for a minimum, then we have to find the derivative with respect to t. This is 5*(25*t-9)/(sqrt(25*t^2-18*t+9)), this derivative is zero at t=9/25=0,36 h = 21.6 min, now to be sure it is a minimum we apply the second derivative criteria that states that if the second derivative at the given critical point is positive it means here we have a minimum, and by calculating the second derivative we find it is 720/(25 t^2 - 18 t + 9)^(3/2) that is positive at t=9/25, then we have our answer. And besides replacing the value of t we get the distance is 12 km.
Answer:
Fnet - Fg
Explanation:
When an object is in an elevator, its weight varies with respect to the direction of movement of the elevator and the elevators acceleration.
The weight, W, of an object can be expressed as;
W = mg
where m is the object's mass, and g is the acceleration due gravity.
If the object is in an elevator that speed up, an apparent weight would be felt since both mass and elevator are moving against gravitational pull of the earth.
So that,
= mg + ma
where: mg is the weight of the object, and ma is the apparent weight.
Apparent weight (ma) =
- mg