Tagged Questions
1
vote
1answer
22 views
How to calculate air resistance of penny dropped from Empire State Building?
If a penny is dropped from the Empire State Building, then its speed, without taking air resistance into consideration, is
$\sqrt{\left(32\frac{\textrm{ft}}{\textrm{s}^2}\right)(1454\textrm{ ...
4
votes
4answers
256 views
Terminal velocity of all falling objects is same?
Ideally 2 objects of different mass and weight will hit the floor at same time because they face same gravitational pull and accelerate. Will the terminal velocity of both objects be same also? and ...
0
votes
2answers
77 views
How to calculate time for ball to reach plane while considering mass, gravity and wind resistance?
The scenario that I'm having is such that a ball of radius $15mm$ is thrown from a location point $\vec{p}=(2, 5, 2)$ in a direction of $\vec{d}=(3, 0, 4)$. The initial velocity is $30m/s$. There were ...
7
votes
4answers
492 views
What causes a soccer ball to follow a curved path?
Soccer players kick the ball in a linear kick, though you find it to turn sideways, not even in one direction. Just mid air it changes that curve's direction. Any physical explanation?
Maybe this ...
1
vote
0answers
73 views
Integration question from book “e: The Story of a Number” by Eli Maor [closed]
In the book 'e: The Story of a Number', a derivation of a parachutist problem is given on pg. 109-110. A parachutist jumps from a plane and at $t=0$ opens his chute. At what speed will he reach the ...
10
votes
4answers
1k views
Acceleration of two falling objects with identical form and air drag but different masses
I have a theoretical question that has been bugging me and my peers for weeks now - and we have yet to settle on a concrete answer.
Imagine two balloons, one is filled with air, one with concrete. ...
4
votes
2answers
108 views
What was the muzzle velocity of a home made gun launch strait in the air if air time was 8.2sec?
I built a potato gun and wanted to calculate the muzzle velocity. I remember from physics that I could run the numbers by calculating time from launch until landing. After pointing strait into the air ...
1
vote
1answer
125 views
How much runway does the space shuttle need to land?
A textbook question proposes the following scenario:
NASA needs to plan emergency landing sites for the Space Shuttle (RIP). There are a number of things to consider. The shuttle touches down no ...
3
votes
1answer
230 views
Finding the diameter a parachute must be to land a probe on Mars at specific speed
Hi I'm trying to solve this textbook example but I don't know where to begin;
NASA has decided to send an experimental probe to Mars. Its weight on earth is $40 kg_f$. When the probe is near ...
1
vote
2answers
121 views
Kinetic Energy of Stone
If a stone is launched upward, of which is subject to gravity and air resistance, which of the following will have a greater kinetic energy? The stone at a point on its way up, or the stone at the ...
2
votes
2answers
170 views
Parabolic motion and air drag
Are this equations correct, in order to calculate the parabolic motion of an arrow with the computation of the drag with the air?
$$
\begin{cases}
x(t)=\left(v_0-\frac{1/2C_DA\rho ...
1
vote
1answer
451 views
Friction due to air drag at high speeds
I am trying to set up this problem, but I am not sure how to go about doing so. (From University Physics, Young & Freedman):
You throw a baseball straight up. The drag force is proportional to
...
4
votes
4answers
2k views
How Felix Baumgartner has reached the speed of sound quickly
I have watched Felix Baumgartner freefall; but I wonder how Felix has reached the speed of sound quickly, in a matter of some seconds, then we had no idea of its speed?
Any explanation please.
0
votes
1answer
157 views
How can the Air friction force be applied to an object?
Suppose we have an object and we throw it straight upward in the air. How do we apply the Air friction force to this object while moving upwards and after that downwards? Sorry if it's easy because ...
1
vote
2answers
424 views
Free fall of two spheres made of same materials, different masses, with air resistance
Two people falling with the same parachute will gain different speeds if their masses are different. The upward air drag will needed to be bigger for a heavier person, since gravitational force is ...
3
votes
2answers
217 views
At what g is terminal velocity not terminal?
How weak would gravity need to be in order for a human to reliably survive the terminal velocity of falling through air?
(Context: watching scifi on a space station with a variety of artificial ...
2
votes
3answers
839 views
What is terminal velocity?
What is terminal velocity? I've heard the term especially when the Discovery Channel is covering something about sky diving. Also, it is commonly known that HALO (Hi-Altitude, Lo-Opening) infantry ...
