Question
4. What is the weight of an object with a mass of 20 kilograms on a planet that has an acceleration of gravity of 9.8 m/s2? (Be sure to sure your work.)
5. A feather and a hammer are in free fall when...
A) gravity and air resistance act on them.
B) weight is the only force acting on them.
C) air resistance is the only force acting on them.
D) gravity is the only force acting on them.
6. If your actual mechanical advantage is 10 J and the theoretical is 40 J, what is your percent efficiency? Hint: % Efficiency = (Actual MA/Ideal MA) * 100
a
0.25%
b
400%
c
25%
d
4%
7. A hammer (500 grams), a small parachute (21 grams), and a baseball (145 grams) are all dropped from a height of 25 meters. The hammer and baseball take about the same amount of time to fall. Which statement describes the time it takes for the parachute to fall?
a
The parachute takes less time to fall because it has the most surface area.
b
The parachute takes longer to fall because of greater air resistance.
c
The parachute takes the same amount of time to fall because the effect of gravity is the same.
d
The parachute takes less time to fall because it has the least mass.
8. You and your friend mow a half acre lawn. You get it done in half the time of your friend. Who did more work?
a
None of the above
b
Your friend, because they did it slower
c
You both did the same amount of work, because time is not relevant to the work completed
d
You, because you did it faster
9. If you took your weight first at sea level and then on top of a very tall mountain, you would find that your weight:
a
stays the same
b
decreases
c
increases
10. An asteroid moves away from our planet. What happens to the gravitational attraction between it and the earth as it zooms away?
A) It does not change.
B) It increases.
C) It decreases.
D) It becomes zero.
5. A feather and a hammer are in free fall when...
A) gravity and air resistance act on them.
B) weight is the only force acting on them.
C) air resistance is the only force acting on them.
D) gravity is the only force acting on them.
6. If your actual mechanical advantage is 10 J and the theoretical is 40 J, what is your percent efficiency? Hint: % Efficiency = (Actual MA/Ideal MA) * 100
a
0.25%
b
400%
c
25%
d
4%
7. A hammer (500 grams), a small parachute (21 grams), and a baseball (145 grams) are all dropped from a height of 25 meters. The hammer and baseball take about the same amount of time to fall. Which statement describes the time it takes for the parachute to fall?
a
The parachute takes less time to fall because it has the most surface area.
b
The parachute takes longer to fall because of greater air resistance.
c
The parachute takes the same amount of time to fall because the effect of gravity is the same.
d
The parachute takes less time to fall because it has the least mass.
8. You and your friend mow a half acre lawn. You get it done in half the time of your friend. Who did more work?
a
None of the above
b
Your friend, because they did it slower
c
You both did the same amount of work, because time is not relevant to the work completed
d
You, because you did it faster
9. If you took your weight first at sea level and then on top of a very tall mountain, you would find that your weight:
a
stays the same
b
decreases
c
increases
10. An asteroid moves away from our planet. What happens to the gravitational attraction between it and the earth as it zooms away?
A) It does not change.
B) It increases.
C) It decreases.
D) It becomes zero.
Answers
Answered by
GPT-4o mini
Let's go through each question step by step.
**4. Weight Calculation**
To find the weight of an object, you can use the formula:
\[
\text{Weight} (W) = \text{mass} (m) \times \text{acceleration due to gravity} (g)
\]
Given:
- Mass (\( m \)) = 20 kg
- Acceleration due to gravity (\( g \)) = 9.8 m/s²
Calculating:
\[
W = 20 \, \text{kg} \times 9.8 \, \text{m/s}^2 = 196 \, \text{N}
\]
So, the weight of the object is **196 Newtons (N)**.
---
**5. Free Fall Conditions**
The phenomenon whereby an object falls under the influence of gravity alone occurs when:
D) gravity is the only force acting on them.
---
**6. Percent Efficiency Calculation**
Given:
- Actual Mechanical Advantage (Actual MA) = 10 J
- Theoretical Mechanical Advantage (Ideal MA) = 40 J
To find percent efficiency, use the formula:
\[
\text{Percent Efficiency} = \left(\frac{\text{Actual MA}}{\text{Ideal MA}}\right) \times 100
\]
Calculating:
\[
\text{Percent Efficiency} = \left(\frac{10 \, \text{J}}{40 \, \text{J}}\right) \times 100 = 25\%
\]
So, the answer is **c) 25%**.
---
**7. Parachute Falling**
The scenario describes a feather and a hammer in free fall with air resistance becoming significant for the parachute. Thus, the statement that describes the time it takes for the parachute to fall is:
b) The parachute takes longer to fall because of greater air resistance.
---
**8. Work Done While Mowing the Lawn**
Work is defined as the force exerted over a distance and does not depend on the time taken. Since both you and your friend mowed the same half-acre lawn, the correct answer is:
c) You both did the same amount of work, because time is not relevant to the work completed.
---
**9. Weight Variation with Altitude**
When measuring weight at sea level and then on a tall mountain, the acceleration due to gravity decreases, leading to a reduction in weight. Therefore:
b) decreases
---
**10. Gravitational Attraction with Distance**
As the asteroid moves away from Earth, gravity decreases because gravitational force is inversely proportional to the square of the distance between the centers of mass. Therefore:
C) It decreases.
---
This covers all the questions efficiently! If you have any more questions or need clarification, feel free to ask.
**4. Weight Calculation**
To find the weight of an object, you can use the formula:
\[
\text{Weight} (W) = \text{mass} (m) \times \text{acceleration due to gravity} (g)
\]
Given:
- Mass (\( m \)) = 20 kg
- Acceleration due to gravity (\( g \)) = 9.8 m/s²
Calculating:
\[
W = 20 \, \text{kg} \times 9.8 \, \text{m/s}^2 = 196 \, \text{N}
\]
So, the weight of the object is **196 Newtons (N)**.
---
**5. Free Fall Conditions**
The phenomenon whereby an object falls under the influence of gravity alone occurs when:
D) gravity is the only force acting on them.
---
**6. Percent Efficiency Calculation**
Given:
- Actual Mechanical Advantage (Actual MA) = 10 J
- Theoretical Mechanical Advantage (Ideal MA) = 40 J
To find percent efficiency, use the formula:
\[
\text{Percent Efficiency} = \left(\frac{\text{Actual MA}}{\text{Ideal MA}}\right) \times 100
\]
Calculating:
\[
\text{Percent Efficiency} = \left(\frac{10 \, \text{J}}{40 \, \text{J}}\right) \times 100 = 25\%
\]
So, the answer is **c) 25%**.
---
**7. Parachute Falling**
The scenario describes a feather and a hammer in free fall with air resistance becoming significant for the parachute. Thus, the statement that describes the time it takes for the parachute to fall is:
b) The parachute takes longer to fall because of greater air resistance.
---
**8. Work Done While Mowing the Lawn**
Work is defined as the force exerted over a distance and does not depend on the time taken. Since both you and your friend mowed the same half-acre lawn, the correct answer is:
c) You both did the same amount of work, because time is not relevant to the work completed.
---
**9. Weight Variation with Altitude**
When measuring weight at sea level and then on a tall mountain, the acceleration due to gravity decreases, leading to a reduction in weight. Therefore:
b) decreases
---
**10. Gravitational Attraction with Distance**
As the asteroid moves away from Earth, gravity decreases because gravitational force is inversely proportional to the square of the distance between the centers of mass. Therefore:
C) It decreases.
---
This covers all the questions efficiently! If you have any more questions or need clarification, feel free to ask.