# Questions tagged [projectile]

This tag is for questions relating to projectile, object moving through space due to the exertion of a force. The path of a projectile is called its trajectory.

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### Draw the angle graphically [closed]

Hi everyone (sorry for the "unclear" title), I'm having trouble graphically representing the point of this: A stone is thrown from the top of a tower with $h = 50\text{m}$ and with a ...
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### When an object is thrown towards the sky it starts to gain potential energy, why?

I didn't think so because when an object is thrown towards the sky it already has kinetic energy and it looses it's energy due to the gravitational force of the earth. When the object looses all of it'...
48 views

### Issue with simplifying the equation related to non-uniform acceleration

I am exploring how the cross sectional area of a drogue chute affects its velocity after travelling a set distance. I got this equation: $$m_1 a = m_2 g - \frac12 c_d \rho A v^2,$$ This covers the ...
3k views

### Error concerning projectile motion in respected textbook?

In the textbook Fundamentals of Physics by R. Shankar of Yale Open Courses, appears the following assertion pertaining to a car driving off a cliff, which seems correct: This is exactly how long it ...
35 views

### If a human falls upright into water, from air at terminal velocity of approx 80m/s, what could be an estimate for their velocity just entering water? [closed]

If a human falls upright into water, from air at terminal velocity of approx 80m/s, what could be an estimate for their velocity just entering water? Like just when they become submerged by the water
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### For an objective falling, reaching terminal velocity and then hitting the ground, how can I find the force it exerts on the ground? [closed]

For example object with v=tanh(0.1213)t/0.01236. m=69kg. I thought I had to use F=mv/t but that just gives the net force of the object while falling. I don't know how to find the force impacting on ...
57 views

### Different results of Range of a projectile [closed]

My question is from the Range of a projectile. Range is displacement of the projectile through X-axis. We all know the formula for the range $R$ of the projectile is $$R=\frac{v_0^2\sin(2\theta)}{g}$$ ...
42 views

### How to find the resultant speed component, and finding the angle in which the trajectory had hit the ground?

When having a trajectory traveling over a projectile, both the vertical and horizontal velocity components must be obtained in order to calculate the resultant velocity. The question is: Why the ...
51 views

### Rocket equation non-constant gravity

I am currently trying to teach myself differential equations and wondered about the following problem. You have an object (a rocket of constant mass $m_r$) and initial velocity $v_0$ that tries to ...
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### Trajectories of projectile based on different speeds of projection [duplicate]

So my teacher was teaching gravitation and an interesting fact that he mentioned was the trajectory of a projectile projected from Earth at a speed equal to escape velocity, is parabolic. Also, he ...
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1 vote
138 views

### Vertical trajectory of a projectile with quadratic drag

I was wondering is there is an equation (or function) that can predict the apogee time and height of an object given its current acceleration and the usual constants ( mass, drag coefficient, cross ...
1k views

### Why does the cross section of a metal after a hypervelocity impact look like that?

Look at this image of a cross section of a piece of (I assume) metal after a hypervelocity impact: I understand where the crater shape comes from, but what puzzles me is the cavity near the bottom: ...
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1 vote
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### What happens to $\frac{d}{dt}\left(\hat{v}\right)$ at the highest point a projectile reaches when launched vertically upwards?

Acceleration is given by $\dot{\vec{v}} = \frac{d}{dt}\left( v \hat{v}\right) = \dot{v} \hat{v} + v \dot{\hat{v}}$. What happens to $\dot{\hat{v}}$ when the direction of velocity flips by $180^o$? E....
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### General solution for the motion of a 1D particle with drag

Consider a particle of mass $m$, with equation of motion $$m\ddot{x}=-U'(x)-f(\dot{x})\dot{x}.$$ I am trying to find an equation of the form $v=g(x)$ so that we can reduce this to an integral of the ...
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### Need help regarding projectile motion

While studying motion in 2D, I came to know that when an object, projected with some initial velocity, making angle $0°$ with the horizontal, will have zero range. Its a bit confusing. The object has ...
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44 views

### Components of velocity in projectile motion [closed]

I came across this question in my physics textbook (Gr12) and I was hoping someone could explain the solution to me A ball is thrown horizontally off a building at $8.2\,\text{m}/\text{s}$. At a ...
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### Is it necessary that a particle attains terminal velocity?

In a viscous medium, consider a ball travelling under the influence of gravity and viscous force. Is it always necessary that during its time in air, the ball attains terminal velocity
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### Question regarding projecticle in freefall disregarding air resistance [closed]

This question is regarding the following problem A stone is thrown up from the top of a tower 20 m with a velocity of 24 m/s at an elevation of $30^\circ$ above the horizontal. Find the horizontal ...
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### How can we measure the kinetic and potential energy of a horizontal projectile?

Say a baseball is shot from a batting machine in a straight line (I don't know much about baseball, but hopefully this makes sense). Normally, when demonstrations on kinetic and potential energy are ...
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1 vote
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### Parabolic(?) projectile orbits as an approximation to elliptical orbits given a rotating Earth

Why is projectile motion a parabola given that the Earth rotates and a parabola is an approximation to an orbit. My current thought is that projectiles don't travel in a parabola because if the Earth ...
126 views

### Ball trajectory in the game of pétanque - unexpected drag results

Context A classmate and I (about college level, not physics majors)need to evaluate the different physical factors at play during a game of pétanque. We thought about estimating the importance of air ...
76 views

### Calculating jumping distance?

I'm trying to figure out how to calculate the jumping distance of a person or animal based on body weight and initial speed, but I can't seem to find any relevant information online about this. Is ...
1 vote
88 views

### How does a mass ejected at escape velocity keep moving till infinity?

I've studied that if a mass is ejected from the surface of the Earth at 11.2 km/s (or at any point above the surface at a lower Ve), it 'escapes' to infinity. Does that not imply a violation in the ...
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### Why is it so much easier to kick a basketball when it is just bouncing back from the ground?

A basketball coach showed me that when you bounce a basketball back from the ground, it is much easier to kick it far away (actually it shoots out like a rocket), but when you want to kick it like a ...
1 vote
65 views

### Would a black hole be slowed down as it passed through a large solid object?

Say I get careless and drop a black hole. It falls through the Earth, passes through the core, and comes out on the other side. Idealised as point masses, the black hole would reach an equal height on ...
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### Why are NASA etc so good at hitting tiny targets in tiny time windows?

NASA have a tendency to arrive at targets that are so far away, within seconds of ETA, and statements like " it's like throwing an object from New York and having it hit a particular key on a ...
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### Height of weight dropped vs launch distance

Say you have a system where a weight drops on an air source, which blows on the ball, launching it. Are there any relations or formulas between the forces at work here? For instance, would there be an ...
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### How does moving the launch area forward impact the area of impact?

If we launch an object in some way, and it lands at distance x, if we move forward the launching mechanism y units forward or backwards, will the landing distance also move forwards or backwards y ...
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### A ball was thrown horizontally but it has zero horizontal initial velocity? [closed]

A question I faced reads "A ball is thrown horizontally from a height of 25m and hits the ground with a speed that is 4 times its initial speed. What is the initial speed?". It said the ...
73 views

### Why catching a ball of high trajectory easier in Cricket match? [closed]

my question is related with Projectile motion, it describes about the high velocity of ball on its trajectory. it asks about the conditions of height, time of flight, range as well.
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### Spin velocity in table tennis

I have read on papers that argued, when flying, we have constant spin velocities $\omega_x, \omega_y, \omega_z$, that primarily depend on the initial spin setting e.g., topspin, bottom spin and ...
59 views

### Time taken for ball to reach down is more? [duplicate]

If we consider a practial situation, where air resistance exists, why does a ball/object take more time to come down than to go up? This seems contradicting to me at the first glance, but I am pretty ...
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### How optimal launching angle is affected by mass?

I'm writing a code to calculate the maximum optimal angle for motion under linear drag and how it's affected by mass. It appears that for the most part this angle is independent of mass and not of ...
1 vote
137 views

### Would an object stop if the only force acting against it is air friction? [closed]

This question has bothered me for some time couple of years ago, so here is the main problem: Suppose that an object of mass $m$, is thrown with horizontal velocity $v$ on a horizontal, frictionless, ...
1 vote
Let's say an object is thrown from Earth with a speed of v at an angle $\theta$. An ellipse is formed with the center of Earth as its foci(given in the figure). We know that \$v_x^2=2GM(\frac{1}{r_x}-\...