# I have to make sample questions for class

• PhysWiz3.14
In summary, the conversation revolved around questions related to gravity, the Earth's orbit around the Sun, and the location where the gravitational pull of the Earth and Moon would cancel. The first question asked for the value of g at a distance three times the Earth's radius, while the second question asked for the speed at which the Earth revolves around the Sun. The third question asked for the location where the gravitational pull of the Earth and Moon would cancel, with three options provided.
PhysWiz3.14
Can someone look these over and answer them so I can make sure my work is correct

1. The value of g at the Earth's surface is about 10 m/s2. What is its value at a distance from the Earth's center that is three times the Earth's radius?

2.Calculate the speed in meters per second at which the Earth revolves around the Sun. Assume the orbit is nearly circular, with radius r=1.5 10^11 m.

3. Somewhere between the Earth and the Moon, the gravitational pull exerted by these two bodies on a space pod would cancel. Is this location nearer the Earth or nearer the Moon?
A) Nearer the Earth.
B) Nearer the Moon.
C) At the half-way point.

Thanks for the help in advance.

Last edited:
Welcome to PF.
FIRST ONE IS A BIT TOO LENGTHY.
SECOND ONE IS A GOOD ONE.
THIRD QUESTION DOES NOT IMPRESS ME MUCH.

1. The value of g decreases as we move away from the Earth's surface. Using the formula g=Gm/r^2, where G is the universal gravitational constant, m is the mass of the Earth, and r is the distance from the Earth's center, we can calculate the value of g at a distance that is three times the Earth's radius. Plugging in the values, we get g= (6.67x10^-11 Nm^2/kg^2)(5.97x10^24 kg)/(3(6.38x10^6 m))^2 = 2.22 m/s^2. Therefore, the value of g at a distance three times the Earth's radius is approximately 2.22 m/s^2.

2. The speed at which the Earth revolves around the Sun is given by the formula v=√(GM/r), where M is the mass of the Sun, r is the distance from the center of the Sun, and G is the universal gravitational constant. Plugging in the values, we get v=√((6.67x10^-11 Nm^2/kg^2)(1.99x10^30 kg)/ (1.5x10^11 m)) = 2.98x10^4 m/s. Therefore, the speed at which the Earth revolves around the Sun is approximately 29,800 m/s.

3. The location where the gravitational pull of the Earth and the Moon cancel out is known as the Lagrange point or the L1 point. This point is closer to the Moon than the Earth. Therefore, the answer is B) Nearer the Moon.

## 1. What is the purpose of making sample questions for class?

The purpose of making sample questions for class is to provide students with a way to practice and reinforce their understanding of the material being taught. Sample questions can also help students prepare for exams or assessments.

## 2. How do you create effective sample questions?

Effective sample questions should cover the main concepts and learning objectives of the lesson and be structured in a way that closely resembles the format of the actual assessment. They should also be clear and concise, avoiding any unnecessary complexity or ambiguity.

## 3. How many sample questions should be included in a set?

The number of sample questions included in a set may vary depending on the length and complexity of the lesson. However, a good rule of thumb is to have at least 10-15 questions to provide students with enough practice and variety.

## 4. Should sample questions be graded or used for practice only?

Sample questions can be used for both grading and practice purposes. Grading sample questions can provide valuable feedback to students on their understanding of the material and help them identify areas where they may need more practice.

## 5. How often should sample questions be used in a classroom setting?

Sample questions can be used as frequently as needed in a classroom setting. They are particularly useful for reviewing material before an assessment or for providing additional practice throughout the course. However, it is important to also incorporate other forms of assessment and learning activities to provide a well-rounded learning experience.

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