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-Dominant- [34]
3 years ago
13

Determine which heat transfers below are due to the process of conduction. I) You walk barefoot on the hot street and it burns y

our toes. II) When you get into a car with hot black leather in the middle of the summer and your skin starts to get burned. III) A flame heats the air inside a hot air balloon and the balloon rises. IV) A boy sits to the side of a campfire. He is 10 feet away, but still feels warm. A) I and II B) III and IV C) I, II, and IV D) II, III, and IV
Physics
2 answers:
Rudik [331]3 years ago
3 0

I) You walk barefoot on the hot street and it burns your toes.

The road is in direct contact with your skin. Thermal energy from the road will transfer to the bottom of your feet, then to the rest of your body. This is an example of conduction.


II) When you get into a car with hot black leather in the middle of the summer and your skin starts to get burned.

Just like in the previous example, the hot leather is in direct contact with your skin (I guess if you're going to drive naked). Thermal energy from the leather will transfe to your skin, then to the rest of your body. This is also conduction.


III) A flame heats the air inside a hot air balloon and the balloon rises.

The flame heats air directly at the bottom of the balloon. The warm air expands and becomes less dense. This will rise and let the unheated, denser air in the balloon fall down toward the flame. This is an example of the convection cycle.


IV) A boy sits to the side of a campfire. He is 10 feet away, but still feels warm.

The campfire heats air directly nearby. The warm air expands and moves away from the fire in all directions, leaving behind unheated, denser air to be heated up. Some of the warm air reaches the boy. This is another example of convection.


The answer is A) 1 and 2.

Shkiper50 [21]3 years ago
3 0

Explanation:the correct answer is A

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3 years ago
A physics student throws a softball straight up into the air. The ball was in the air for a total of 3.56 s before it was caught
meriva

Answer:

The initial velocity of the softball is 14.711 meters per second.

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From statement we must understand that the student threw the softball upwards and it is caught at original position 3.56 seconds later. Initial and final heights, time and gravitational acceleration are known and initial speed is unknown. The following equation of motion is used:

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Where:

y_{o} - Initial height of the softball, measured in meters.

y - Final height of the softball, measured in meters.

v_{o} - Initial velocity of the softball, measured in meters per second.

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g - Gravitational acceleration, measured in meters per square second.

If we know that y = y_{o}, t = 3.56\,s and g = -9.807\,\frac{m}{s^{2}}, the initial velocity of the softball is:

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