Question

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.

Answer 1

Here are the answers to the questions based on physics principles:

5. A feather and a hammer are in free fall when...
**b - weight is the only force acting on them.**
(Note: In free fall, the only force acting on them effectively is gravity, and we can consider air resistance negligible for a feather and hammer in a correct free-fall scenario.)

6. If your actual mechanical advantage is 10 J and the theoretical is 40 J, what is your percent efficiency?
**c - 25%**
(Percent efficiency = (10 J / 40 J) * 100 = 25%)

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?
**b - The parachute takes longer to fall because of greater air resistance.**
(The parachute has a larger surface area, which increases air resistance and causes it to fall slower than the hammer and baseball.)

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?
**c - You both did the same amount of work, because time is not relevant to the work completed.**
(Work is defined as force multiplied by distance, and if both lawns are the same size, the work done is the same regardless of time taken.)

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:
**b - decreases**
(Weight decreases with altitude because gravitational force decreases as distance from the Earth increases.)

10. An asteroid moves away from our planet. What happens to the gravitational attraction between it and the earth as it zooms away?
**c - It decreases.**
(Gravitational attraction decreases with the square of the distance between two objects.)

These answers are based on fundamental physics concepts.