Answer:
D. It uses boron so that electrical conduction is due to the movement of a positive charge.
Explanation:
Please mark me brainliest
Answer is D.
Speed:
Use relative speed to simplify the situation. Since the trains are moving in opposite directions, you can add the speeds and pretend the first train is stationary (moving at 0m/s) and the second train is moving at 50m/s.
Distance:
The front of the second train needs to travel 120m to get from the front to the back of the first train. When the front of the second train is at the back of the first train, the back of the second train is still 10m in front of the first train. The back therefore has to travel 130m to clear the first train. The total distance over which the trains are overlapping in this scenario is therefore 120 + 130 = 250m.
You have speed and you have distance so now just calculate time:
v = d / t
50 = 250 / t
t = 5s
The density of the object is approximately 1.91 kg per m³.
42 kg is a measure of mass, and 22 m³ is a measure of volume. Knowing this, you can use the relationship
to solve for the object's density.
42 kg
22 m³
1.91 kg per m³.
239.7
To figure it out, add 273 to the temp in Celsius and you have temp in Kelvin!!