Answer:
In other words, if two objects are the same size but one is heavier, the heavier one has greater density than the lighter object. Therefore, when both objects are dropped from the same height and at the same time, the heavier object should hit the ground before the lighter one.
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thank you for answer ☺️☺️
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imsogorgoeus imsogorgoeus
Answer:
If two objects are the same size but one is heavier, the heavier one has greater density than the lighter object. Therefore, when both objects are dropped from the same height and at the same time, the heavier object should hit the ground before the lighter one
Explanation:
Here is a better example. In this case I have a crumpled up piece of paper and some type of foam board. The paper has a mass of 5 grams and the board is 240 grams. Just as a hint, that's a big difference in mass. But which one hit the ground first? Yup, the piece of paper. Awesome, right? And then when I turn the foam board so that the thin side faces down, BOOM. They both hit the ground at the same time.
So, what hits the ground first? Everything. Above you can see it all. Both heavier and lighter things can fall faster. Clearly, you can't just say "heavier is faster".
Acceleration of Falling Objects
Let's look at the case of a falling bowling ball and basket ball. This is a force diagram showing the two objects.
The bowling ball has a greater mass so it also has a greater gravitational force. You can calculate this gravitational force as the product of the mass (m) and the gravitational field (g). There is something else that depends on the mass, the acceleration. If there is only one force on an object then the following would be true (in one dimension):
Since both the acceleration AND the only force depend on mass, I can write:
Heavier things have a greater gravitational force AND heavier things have a lower acceleration. It turns out that these two effects exactly cancel to make falling objects have the same acceleration regardless of mass.
Air Resistance
Clearly, I didn't fully address all the issues above. If all objects have the same falling acceleration, then why did the crumpled up paper hit the ground before the foam board? The problem is that I left off a force - the air resistance force.
Here's another experiment. Put your hand out the window of a moving car. What do you feel? You can feel the air pushing against your hand. If the car drives faster, the air resistance force gets larger. If you make your hand into a fist instead of an open hand, the force decreases.
This air resistance force is really just the sum of the tiny impacts with your hand and the air. It depends on the air speed as well as the size of the object.
Then what happens as you drop both a foam board and a crumpled piece of paper? At first, they have the same acceleration since they both have a zero velocity which makes zero air resistance force. However, after some short time the forces might look like this:
The foam board has a larger gravitational force but it also has a very large air resistance force. The net (total) force on the foam board will give it a smaller acceleration than paper.
But what about the basketball and the bowling ball? Shouldn't they have different accelerations? Technically, yes. Let me redraw the force diagrams for these two objects and include air resistance.
For these objects, the gravitational force is huge in comparison to the air resistance force. Essentially, it doesn't do much to change the falling acceleration of these objects. But when does it matter? This is a tough question. First, anything at a very low speed will have a mostly negligible air resistance and at high speed will have significant air resistance. Here are some cases where you would NOT ignore air resistance:
- A falling piece of paper or a feather.
- A falling human at high speeds (a sky diver).
- A professionally thrown baseball (100 mph).
- A ping pong ball.
- Tiny rocks or gravy.
I know that doesn't fully answer the question about air resistance, but it gives you an idea of where to start. But it turns out that there are many situations where a heavier object does indeed hit the ground before a lighter object (because of air resistance). I guess this is why Aristotle and many others think this is always true.
Oh, Veritasium has a some great videos about falling objects. Here are my favorite three videos with questions to consider.
A physics problem from Science Buddies
Key concepts Physics Free fall Forces Gravity Mass Inertia
Introduction
Have you ever wondered how fast a heavy object falls compared with a lighter one? Imagine if you dropped both of them at the same time. Which would hit the ground first? Would it be the heavier one because it weighs more? Or would they hit the ground at the same time? In the late 1500s in Italy the famous scientist Galileo was asking some of these same questions. And he did some experiments to answer them. In this activity you'll do some of your own tests to determine whether heavier objects fall faster than lighter ones.
Background
In fourth-century B.C. Greece the philosopher Aristotle theorized that the speed at which an object falls is probably relative to its mass. In other words, if two objects are the same size but one is heavier, the heavier one has greater density than the lighter object. Therefore, when both objects are dropped from the same height and at the same time, the heavier object should hit the ground before the lighter one. Is this true?
Some 1,800 years later, in late 16th-century Italy, the young scientist and mathematician Galileo Galilei questioned Aristotle's theories of falling objects. He even performed several experiments to test Aristotle's theories. As legend has it, in 1589 Galileo stood on a balcony near the top of the Tower of Pisa and dropped two balls that were the same size but had different densities. Although there is debate about whether this actually happened, the story emphasizes the importance of using experimentation to test scientific theories, even ones that had been accepted for nearly 2,000 years.
Materials • Two balls of the same size, but different mass. For example, you could use a metal and a rubber ball or a wooden and a plastic ball, as long as the two balls are about the same size. If two spherical balls like this are unavailable, you could try something like an apple and a similar-size round rock. • A ladder or step stool
• A video camera and a helper (optional)
Preparation • You will be dropping the two balls from the same height, at the same time. Set up the ladder or step stool where you will do your test. If you are using a heavy ball, be sure to find a testing area where the ball will not hurt the floor or ground when it lands. • If you are using a video camera to record the experiment, set up the camera now and have your helper get ready to record.
• Be careful when using the step stool or ladder.
Procedure • Carefully climb the ladder or step stool with the two balls. • Drop both balls at the same time, from the same height. If you are using a video camera, be sure to have your helper record the balls falling and hitting the ground.
• Did one ball hit the ground before the other or did both balls hit the ground at the same time?
• Repeat the experiment at least two more times. Are your results consistent? Did one ball consistently hit the ground before the other or did both balls always hit the ground at the same time? • If you videotaped your experiments, you can watch the recordings to verify your results.
• Can you explain your results?
• Extra: Try this experiment again but this time use balls that have the same mass but are different sizes. Does one ball hit the ground before the other or do they hit it at the same time?
• Extra: Try testing two objects that have the same mass, but are different shapes. For example, you could try a large feather and a very small ball. Does one object hit the ground before the other or do they hit it at the same time?
• Extra: You could try this experiment again but record it using a camera that lets you play back the recording in slow motion. If you watch the balls falling in slow motion, what do you notice about how they are falling over time? Are both objects always falling at the same speed or is one falling faster than the other at certain points in time?
Observations and results
Did both balls hit the ground at the same time?
You should have found that both balls hit the ground at roughly the same time. According to legend, this is what Galileo showed in 1589 from his Tower of Pisa experiment but, again, it's debated whether this actually happened. If you neglect air resistance, objects falling near Earth’s surface fall with the same approximate acceleration 9.8 meters per second squared (9.8 m/s2, or g) due to Earth's gravity. So the acceleration is the same for the objects, and consequently their velocity is also increasing at a constant rate. Because the downward force on an object is equal to its mass multiplied by g, heavier objects have a greater downward force. Heavier objects, however, also have more inertia, which means they resist moving more than lighter objects do, and so heaver objects need more force to get them going at the same rate.
More to explore
Elephant and Feather—Free Fall , from The Physics Classroom
Engines of Our Ingenuity: No. 166: Galileo's Experiment , from John H. H. Lienhard, University of Houston
Video: Fall of 2 Balls of Different Weights , from Matthias Liepe, Cornell University
What Goes Up, Must Come Down: Conduct Galileo's Famous Falling Objects Experiment , from Science Buddies
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