Which describes what happens when you fly 10 km above the Earth’s surface?
Select one:
a. mass decreases, weight increases
b. mass decreases, weight decreases
c. mass decreases, weight remains constant
d. mass remains constant, weight decreases
1.06 L of water is equivalent to
Select one:
a. 0.001 06 mL.
b. 10.6 mL.
c. 106 mL.
d. 1060 mL.
The SI standard units for length and mass are
Select one:
a. centimeter and gram.
b. meter and gram.
c. centimeter and kilogram.
d. meter and kilogram.
The weight of an object ____.
Select one:
a. is the same as its mass
b. depends on its location
c. is not affected by gravity
d. is always the same
A measurement is said to have good precision if it
Select one:
a. agrees closely with an accepted standard.
b. agrees closely with other measurements of the same quantity.
c. has a small number of significant figures.
d. has a large number of significant figures.
help with chemistry questions!!?
2018-06-15 12:27 am
回答 (2)
2018-06-15 1:01 am
1.
The mass of an object is constant.
The weight of an object is due to the gravitational force acting on the subject. As the gravitation force is inversely proportional to the square of the distance between the object and the center of the Earth, the weight decreases when the object is 10 km above the Earth's surface.
The answer: d. mass remains constant, weight decreases
====
2.
1 L = 1000 mL
Hence, 1.06 L = (1.06 L) × (1000 mL/L) = 1060 mL
The answer: d. 1060 mL
====
3.
The standard unit for length is meter, and that for mass is gram.
The answer: b. meter and gram.
====
4.
The mass of an object is constant, while the weight of an object is due to the gravitational force acting on the subject. As the gravitation force is inversely proportional to the square of the distance between the object and the center of the Earth, it depends on the location of the object.
The answer: b. depends on its location
====
5.
Good precision means that the measurement has a large number of significant figures.
Good accuracy means that the measurement agrees closely with the accepted value.
The answer: d. has a large number of significant figures.
The mass of an object is constant.
The weight of an object is due to the gravitational force acting on the subject. As the gravitation force is inversely proportional to the square of the distance between the object and the center of the Earth, the weight decreases when the object is 10 km above the Earth's surface.
The answer: d. mass remains constant, weight decreases
====
2.
1 L = 1000 mL
Hence, 1.06 L = (1.06 L) × (1000 mL/L) = 1060 mL
The answer: d. 1060 mL
====
3.
The standard unit for length is meter, and that for mass is gram.
The answer: b. meter and gram.
====
4.
The mass of an object is constant, while the weight of an object is due to the gravitational force acting on the subject. As the gravitation force is inversely proportional to the square of the distance between the object and the center of the Earth, it depends on the location of the object.
The answer: b. depends on its location
====
5.
Good precision means that the measurement has a large number of significant figures.
Good accuracy means that the measurement agrees closely with the accepted value.
The answer: d. has a large number of significant figures.
2018-06-15 4:19 am
Chemistry question.....
1. This is an example of a question with poorly constructed answer choices since only one choice contains the right answer and the other part is ambiguous. Weight is a force and is proportional to acceleration (F=ma, Newton's second law). Even if flying level, and only experiencing the acceleration due to gravity at 10 km, the weight of a person will be essentially indistinguishable from the weight at the ground. The force of gravity is still quite strong even at 250 km above the surface (orbit of ISS), and even the orbit of the moon, which is of course what helps keep the Earth and Moon in orbit around their center of mass.
Questions 2, 3 and 4 are "d", "d" and "b", respectively. The gram is NOT the SI unit for mass, the kilogram is.
As for the 5th question, the indicator of precision is the closeness to other measurements of the same thing. The more agreement between measurements, the more precision in the measurements. Here's another reference to reinforce my point. https://labwrite.ncsu.edu/Experimental%20Design/accuracyprecision.htm
The number of significant digits is related to precision, usually, the more precise the measurement, the greater the number of significant digits, but the number of significant digits is not a definition of precision.
1. This is an example of a question with poorly constructed answer choices since only one choice contains the right answer and the other part is ambiguous. Weight is a force and is proportional to acceleration (F=ma, Newton's second law). Even if flying level, and only experiencing the acceleration due to gravity at 10 km, the weight of a person will be essentially indistinguishable from the weight at the ground. The force of gravity is still quite strong even at 250 km above the surface (orbit of ISS), and even the orbit of the moon, which is of course what helps keep the Earth and Moon in orbit around their center of mass.
Questions 2, 3 and 4 are "d", "d" and "b", respectively. The gram is NOT the SI unit for mass, the kilogram is.
As for the 5th question, the indicator of precision is the closeness to other measurements of the same thing. The more agreement between measurements, the more precision in the measurements. Here's another reference to reinforce my point. https://labwrite.ncsu.edu/Experimental%20Design/accuracyprecision.htm
The number of significant digits is related to precision, usually, the more precise the measurement, the greater the number of significant digits, but the number of significant digits is not a definition of precision.
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