Tagged Questions
5
votes
1answer
60 views
In tennis, why does topspin serve bounce higher than flat serve?
When receiving servers (while playing tennis), I've noticed that the tennis ball seems to bounce up higher on me when the server uses a topspin serve than when the server hits a flat serve. Why is ...
-1
votes
0answers
29 views
Velocity versus time graph [closed]
A stone is thrown at an angle of $45^0$ above the horizontal x-axis in the +x-direction. If air resistance is ignored, which of the velocity versus time graphs shown above best represents $v_x$ ...
1
vote
3answers
121 views
How can I solve for time without knowing the vertical velocity?
A guy posted this problem on a forum:
There is a bird sitting on a pole of height h. you throw a rock at it and the moment the rock leaves your hand the bird starts flying horizontally away from ...
1
vote
1answer
135 views
Projectile along incline [closed]
A particle is projected with velocity $u$ from the bottom of an inclined plane whose inclination with the horizontal is $\beta$. If afterwards the projectile strikes the inclined plane perpendicular ...
0
votes
0answers
37 views
Maximum Height of Potato [closed]
I have a bit of a problem. We made potato launchers and launched the potato's into the air. I need to find out what the maximum height my potato reached was. The givens I have are the following:
Mass ...
0
votes
2answers
74 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 ...
0
votes
0answers
40 views
Trajectory the body thrown at angle to the horizon
I need to simulate some body, thrown at some angle to the horizon and at some azimuth.
What would be $x(t)$, $y(t)$ and $z(t)$ involving $g(h)$, air resistance (with $\rho(h)$), Coriolis effect and ...
2
votes
2answers
83 views
Parabolic motion (experiment)
We performed a laboratory, performing six releases of a sphere with angles $15^\circ,30^\circ,45^\circ,60^\circ,75^\circ,40^\circ$ a parabolic movement, took five distances for each angle, the initial ...
7
votes
4answers
467 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 ...
0
votes
3answers
95 views
Solve for Initial Velocity of a projectile given Angle, Gravity, and Initial and Final positions?
I've found equations http://www.physicsclassroom.com/Class/1DKin/U1L6a.cfm for solving everything (and rearranged to solve everything) to do with projectile motion EXCEPT this, even though it should ...
1
vote
3answers
111 views
Projectiles and escape velocity
Q: The escape velocity for a body projected vertically upwards from the surface of earth is 11 km/s. If the body is projected at an angle of $45^\circ$ with vertical, the escape velocity will be?
...
0
votes
1answer
45 views
Projectile's angle in midflight
For a missile travelling from (0,0) at angle $\theta$ (to the horizontal) and initial velocity $u$, the y (vertical) position at time t is given by
$s_{y} = u\sin (\theta) t - 0.5gt^{2}$
and the x ...
1
vote
0answers
70 views
What is the initial velocity of a projectile so that it passes through a target point in its trajectory? [closed]
Let's say I have a projectile being thrown by a player in my 2-D game. I want to work backwards and find the initial velocity to apply to the projectile such that it passes through a target point in ...
1
vote
4answers
141 views
How to get the angle needed for a projectile to pass through a given point for trajectory plotting
I am trying to find the angle needed for a projectile to pass-through a given point.
Here is what I do know:
Starting Point $(x_0,y_0)$
Velocity
Pass-through point $(x_1, y_1)$
I also need to ...
1
vote
0answers
51 views
I need help with the following Physics' questions [closed]
I need to know which formulas and the step-by-step answers for the following physics questions:
1. You throw a ball upward with an initial speed of 7.0 m/s, and it returns to your hand o.92 ...
2
votes
3answers
145 views
In projectile motion, what does it mean for the motion along the $x$ and $y$ axis to be independent?
In projectile motion, what does it mean for the motion along the $x$ and $y$ axis to be independent?
This question is referring to the concept of projectile motions.
1
vote
1answer
175 views
Monkey and tree - projectile motion
The famous scenario: A hunter is trying to shoot a Monkey hanging from a tree. However, this question doesn't mention the monkey jumping down from the tree or trying to escape. (The hunter uses a ...
1
vote
1answer
146 views
Work done in projectile motion
A projectile is shot at some inclination to the ground. It falls at another point having R distance from the initial point on the ground. Is there any work done?
If initial velocity vector is $(u\cos ...
1
vote
1answer
142 views
Projectile motion in two and three dimensions question?
So I bought this book in the library and physics fascinates me and I found this quote in the book " Galileo has proved that when any effects due to air resistance
are ignored, the ranges for ...
3
votes
2answers
166 views
Finding optimal angle for projectile, taking into account linear (Stokes) drag
If you throw a projectile from the ground at a certain angle, it's not hard to see that, assuming we're in a vacuum, throwing it at 45º from the ground will always make it go farthest before it hits ...
0
votes
0answers
42 views
Physics homework about thrown projectiles [closed]
I've trouble figuring out 2 questions:
A dart player throws a darts horizontally at a speed of 13.5 m/s. The dart hits the board 0.37 m below the height from which it was thrown. How far away is ...
1
vote
1answer
97 views
Idealized trajectory from sloped surface
I am a GIS programmer implementing a visualization.
I am modeling the idealized trajectory of a particle ejected from a volcanic vent using:
$$\text{distance} = \frac{(v^2 \times ...
1
vote
2answers
111 views
Estimating atmospheric friction by measuring the change in velocity of a ball thrown straight upwards
Imagine I throw a ball straight upwards with some velocity $v_1$, and filming the ball with a camera, I can estimate a velocity $v_2$ (along the same vector) after the ball has moved a distance $D$. ...
-1
votes
2answers
328 views
Work done by the air resistance [closed]
A ball of mass 0.37 kg is thrown upward along the vertical with a
initial speed of 14 m / s, and reaches a maximum height of 8.4 m.
a) What is the work done by air resistance on the ball? b) ...
0
votes
2answers
165 views
Calculating vertical velocity component of a particle with mass, given the hit point of parabolic motion
Consider the following situation:
I have a particle with a given mass that at a given instant of time (let's say $t_{0}$) is placed at the system origin. The particle has a constant velocity ...
0
votes
0answers
71 views
Downhill projectile question [closed]
I have to solve the following problem:
A hill is sloped downward at an angle $\theta$ with respect to the horizontal. A projectile of mass $m$ is fired with speed $v_0$ perpendicular to the hill. ...
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 ...
7
votes
1answer
249 views
One strategy in a snowball fight
Here's a common college physics problem:
One strategy in a snowball fight is to throw a first snowball at a
high angle over level ground. While your opponent is watching the
first one, you ...
2
votes
2answers
187 views
How do I approach this conservation of energy problem, symbolically
In the absence of nonconservative forces such as friction and air resistance, the total mechanical energy in a closed system is conserved. This is why that when I toss an object directly upwards, the ...
4
votes
2answers
104 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 ...
0
votes
0answers
65 views
I'm having trouble understanding the dimensions of this falling body problem
I'm working with this:
A 50 kg mass is shot from a cannon straight up with an initial
velocity of 10m/s off a bridge that is 100 meters above the ground.
If air resistance is given by 5v ...
3
votes
1answer
211 views
How long will it take for a bullet to reach a Geostationary orbit?
I'm curious to know this. Neglect air friction and imagine a bullet that were shot normal to the Earth's surface, from the Equator. I will have to consider the Coriolis effect and so I expect the path ...
3
votes
2answers
189 views
Projectile motion along the earth
Suppose a projectile is launched from the Earth's surface with initial velocity $v_0$ well below speed of light and initial angle $\theta_0$ with respect to the vertical line perpendicular to the ...
1
vote
2answers
116 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
169 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 ...
2
votes
1answer
113 views
Parabolic Motion
I was wondering if I was right about this simple problem:
A projectile is shot at an angle of 37.0° with the horizontal. The velocity of the projectile at its peak height is 16 m/s.
Then I was told ...
3
votes
3answers
417 views
Free falling objects
My teacher and I are in the middle of an argument because she says that if you were to drop two objects at the same time and the same height, but with different initial velocities, both of them would ...
1
vote
1answer
410 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
...
26
votes
6answers
22k views
Could someone jump from the international space station and live?
Felix Baumgartner just completed his breathtaking free-fall skydiving jump from $120,000\,\text{feet} = 39\,\text{km}$ above the Earth, breaking the speed of sound during the process.
I was wondering ...
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
89 views
Time of a ball going up and down with air resistance
A ball is shot directly upward, and then it comes back to the place where it was shot. Suppose we have air resistance. Suppose $t_1$ is the time period from the moment that the ball was shot to the ...
0
votes
1answer
156 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 ...
0
votes
1answer
126 views
Proving $t=(1+\sqrt{1+2hg/v^2 } ) (v/g)$ for a thrown ball
If we throw a ball from the hight point $h$ from the earth, with initial velocity $v’$, how to prove that the time it takes the ball to reach the earth is given by:
...
1
vote
2answers
1k views
Equations for an object moving linearly but with air resistance taken into account?
I know (from Kinematics) that for an object moving linearly with an acceleration and without air resistance the following equations can be used to determine v(velocity) or x(position of the object) at ...
0
votes
0answers
200 views
Projectile Motion
I know the angle at which a projectile is launched, how far it needs to go, and also the maximum height. How can I find the initial velocity needed (disregarding air resistance)?
Currently, I am ...
2
votes
1answer
487 views
The trajectory of a projectile launched from a hilltop
Here is the problem:
A boy stands at the peak of a hill which slopes downward uniformly at angle $\phi$. At what angle $\theta$ from the horizontal should he throw a rock so that it has the greatest ...
3
votes
3answers
391 views
Does wind speed things up or accelerate things?
This question may seem odd, but I can't think of anything better. So I'll go straight to the point.
Let's say there's a projectile in air going east, shot at a certain angle, with a certain speed. ...
0
votes
1answer
342 views
How calculate the angle to launch an object at the maximum distance?
Suppose that you want to launch an object that travels the longest distance, given the starting speed (or the force applied). You have to determine the angle that al you to reach the longest distance, ...
1
vote
1answer
690 views
Trajectory of projectile thrown downhill
I'm teaching myself mechanics, and set out to solve a problem determining the optimum angle to throw a projectile when standing on a hill, for maximum range. My answer seems almost plausible, except ...
1
vote
1answer
1k views
Simple Projectile Motion Question
A volcano erupts 50m below the sea level. A rock leaves the crater at 20 m/s at an angle 30 deg with the vertical line. The rock has a mass of 15kg. IGNORE WATER RESISTANCE. It gets out of the water, ...
