On a summer day, a scooter rider feels more comfortable while on the move than while at a stop light because ____
Scooter Rider Comfort Explained
A scooter rider feels more comfortable when moving compared to being stopped because of improved heat dissipation from the body.
Heat Transfer Principles
Human bodies generate heat continuously through metabolic processes. Maintaining a comfortable body temperature requires balancing heat generated internally and absorbed from the environment with heat lost to the surroundings. Key heat loss mechanisms are convection, radiation, evaporation, and conduction.
Motion Enhances Heat Loss
- Convection: When the scooter is in motion, air moves rapidly across the rider's body. This increased airflow sweeps away the layer of warm air surrounding the body, replacing it with cooler ambient air. This significantly boosts heat loss via convection.
- Radiation: While convection is dominant, the constant airflow also aids in heat loss through radiation by preventing the build-up of a hot micro-environment around the rider.
Stillness Reduces Heat Loss
When the scooter stops (e.g., at a traffic light), the airflow over the rider's body drastically reduces. This lack of air movement greatly diminishes heat loss through convection. As the body continues to generate heat, it accumulates, leading to a feeling of warmth and discomfort.
Conclusion
Therefore, the primary reason for increased comfort while moving is the enhanced rate of heat loss through convection and radiation due to the forced airflow. This aligns with the principle that more heat is lost by convection and radiation while in motion.
Correct Option Analysis:
Option C correctly identifies that more heat is lost by convection and radiation while in motion, which directly explains the increased comfort felt by the rider.
Important Questions from Convection
An ic engine has a bore and a stroke length of 4 cm each. The total surface area through which heat transfer takes place in cm2 is.
Which of the following is not the regimes of pool boiling?
Nucleate boiling regime is formed approximately between
[ΔTexcess = excess temperature]Analogy between momentum and heat transfer is known as
For flow through a pipe of radius R, the velocity and temperature distribution are as follows:
\(u\left( {r,x} \right) = {C_1},and\ T\left( {r,x} \right) = {C_2}{\left[{1 - (\frac{r}{R})^3} \right]}\), where C1 and C2 are constants. The bulk mean temperature is given by \({T_m} = \frac{2}{{{u_m}{R^2}}}\mathop \smallint \limits_0^R u\left( {r,x} \right)T\left( {r,x} \right)rdr,\)
with Um being the mean velocity of flow. The value of Tm is
