B) Moving with zero acceleration.
Explanation:
Acceleration is defined as the rate of change of the velocity per unit time:
In a velocity-time graph, this ratio corresponds to the slope of the curve. In fact:
(change in velocity) corresponds to the increase in the y-axis
(change in time) corresponds to the increase in the x-axis
So, acceleration corresponds to the slope of the curve in a velocity-time graph. For cart C, the slope is zero, therefore the acceleration is also zero.
You can detect infrared rays by locating the heat.
Conduction is what you're looking for. The two substances are in contact, so heat flows from the warmer to the cooler until they equalize.
1. 0°C
2. Motion
3. Joules
4. Thermometer
5. Gas
6. Less
7. Temperature