Object moving through space due to the exertion of a force.

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990 views

What is the most efficient machine for translating gravitational potential energy of one mass into kinetic energy of a different mass?

As the question states, what is our current best machine for translating falling gravitational potential energy, such as a large weight, into launching a smaller projectile vertically? A lever? A ...
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3answers
74 views

If two objects have the same drag coefficient, but one is much heavier, would it fall faster?

Not sure this is a good example but imagine we have two feathers, both with exactly the same drag coefficient, they have the exact same shape and everything, but the only difference is that one of ...
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1answer
97 views

How does the height reached by a projectile of given flight time depend on air resistance?

Suppose we fire a cannonball straight up. We measure the duration of its flight and use that to estimate the height it reached. Does including air drag increase or decrease the estimated height, ...
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3answers
449 views

Ice/Melting Bullet

I was watching a TV show where a criminal used a bullet made out of blood, so that after entering the body the "evidence" (the bullet) melted away. I was wondering if it were possible to do something ...
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4answers
167 views

Is it possible to prove that projectiles with drag will not travel in a parabola under the theory of classical mechanics?

Can you prove that projectiles will travel in a parabola, provided the acceleration due to gravity $g$ does not vary significantly along the trajectory? This should take air resistance into account. I ...
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1answer
81 views

Falling metal cylinders more devastating than a nuke?

I just saw G.I JOE - Retaliation. In the movie the bad guys (spoiler alert) Could this device cause more destruction than a nuclear weapon? If so, how?
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1answer
102 views

Minimize initial velocity of projectile to arbitrary point

I'm supposed to shoot a projectile from the origin to a point $(x_0 , y_0)$ with minimal initial velocity $v_0$. (no air resistance; regular gravity) The flight time should be $T=\frac{x_0}{v_x}$. ...
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1answer
460 views

Dropping an object from a plane [closed]

I've done this before, but it's been a long time. Using trigonometric functions, I've been asked to solve the following problem. However, I'm at a complete loss as to how to do it. I have 5 questions ...
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2answers
19k views

Finding the drag force (Air resistance force) for accelerated ball?

As you know if I want to find the force for an accelerated object I will use the law $F_o=ma$ so I can get the affecting force of it. But there is another force affecting against the object. It's the ...
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1answer
325 views

If someone shoots a gun (45 caliber) at someone holding up a table or desk 10 feet away, does it slow or turn the bullet away?

Assume it's a standard .45 caliber handgun. Shooter is 10 feet away, and we hold a desk, mini-table, blackboard, etc on our chests(to protect vitals). How do you figure out the bullet's decrease in ...
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4answers
130 views

Force required to send ball in set trajectory

If I have a desired 2D trajectory where I know the desired speed of my ball and desired path, and a ball that starts at (x=0,y=0), how can I calculate the required force / point at which the force ...
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1answer
101 views

Whether a large or a small ball fall faster in the air?

Given a ball falling under gravity is subjected to air resistance, after performing a differential to the drag equation, I get: $$g-Z(v^2)/r = a = v',$$ (where $Z$ is a constant.) How can I know ...
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3answers
661 views

Coriolis force on bullet vs airplane

Why do airplanes experience negligible Coriolis force while bullets experience the Coriolis force in long range shooting, even though the mass of airplane is much bigger than a bullet?
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1answer
62 views

Problem with formula for parabolic motus

I know that the path made by an object thrown in air with velocity $v_0$ with an angle $\alpha$ is: $$y=x \cdot\tan \alpha - \frac {gx^2}{2v_0^2\cdot \cos^2 \alpha} $$ At school we had to use this ...
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1answer
105 views

Projectile motion with drag force of the form $\vec f =-k \vec v$ [closed]

An object is fired with initial velocity $v_0$ at inclination angle $\theta$ above the horizontal. Drag force in the air is taken into account and is of the form $\vec f =-k \vec v$. Knowing that the ...
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3answers
708 views

Can a bullet really fly through space forever?

Some people says that if it would be possible to shoot a bullet so high that it would get over the Earth gravitational pull, the bullet could fly through space forever, because of no deceleration of ...
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1answer
857 views

3D ballistic trajectory with quadratic drag. Calculating position and velocity at time $t$

A particle starts at the origin and has an initial velocity represented by a 3D vector. The particle experiences gravity and air resistance with quadratic drag (based on velocity^2). What I've been ...
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5answers
145 views

Why is the independence of orthogonal vector-quantities always implicit in books/lectures?

The "theorem" that I can "just" separately deal with orthogonal quantities (like horizontal and vertical force or velocity, etc), I never found explicitly mentioned, but just implicitly in the ...
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2answers
239 views

Can a bullet leave a gun and tumble to the ground?

This question seems to have been asked a few times in different configurations, but none of them answer my variation. I've struggled to understand this for nearly 15 years and had conflicting answers ...
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2answers
2k views

Finding the optimal angle of a projectile motion [closed]

I am trying to solve a task in which I need to calculate the optimal angle($\alpha$) with which the projectile will land the furthest from a height ($h$), so what I basically have is the equations for ...
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2answers
1k views

Projectile Motion Question involving a ball and a ramp inclined at an angle

The question is to finde the initial horizontal velocity of the ball at end of the ramp, where it is released. I know how to do this using gravitational potential energy and kinetic energy ($v=\sqrt{...
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2answers
3k 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 ...
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1answer
866 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 ...
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1answer
128 views

Would a projectile keep going forever in empty space?

Would a projectile fired in space and assuming there were no stars or planets in the way, would the projectile continue on to infinity, since the x-component of the projectile's velocity never changes ...
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2answers
48 views

Terminal velocity of mentos [closed]

If somebody throws a mentos downwards (vertically) faster than the terminal velocity of a mentos, from the height at which the terminal velocity is reached from a falling mentos, will the mentos hit ...
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1answer
59 views

​Universe as a projection of something

Who has proposed this and is there an experimental proof? Where can I start to learn about this?
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1answer
79 views

At a fixed inital velocity, What throwing angle will give the projectile the most trajectory length? [closed]

This is a diagram of a projectile motion: Given a constant initial velocity, What angle gives the most trajectory length? By length I mean the length of the parabola from the point the ball is shot ...
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1answer
717 views

How is the fall time for a parachute affected by the mass of the load?

Why do parachutes with a heavier load fall faster than a parachute with a lighter load?
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1answer
346 views

How much does air resistance affect the angular velocity of a golf ball?

I'm modeling the flight trajectory of a golf ball, and using angular velocity to calculate the Magnus force. Currently, I'm assuming angular velocity to be fixed throughout the ball's flight. How ...
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2answers
516 views

Uniformly Accelerated Motion question

A ballast bag is dropped from a balloon that is 300 m above the ground and rising at 13 m/s. For the bag, find the maximum height reached. Now the book gives me this answer - $V_i$ = initial ...
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3answers
140 views

Projectile motion where gravity is a function of $y$

I know what are the laws that describe the projectile motion, and in particular I need to compute the vertical displacement of the projectile at any time $t$: $$ y = y_0 + v_0\sin(\theta)\,t - \frac{...
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1answer
159 views

What is the point of this type of graph? (Projectile) [closed]

What is the point of graphing vs range, during kinematic motion?
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1answer
60 views

Projectile motion. Is there a point where sum of the forces is 0?

Body of mass m, is thrown with initial speed, at an angle α from a horizon. Neglecting wind resistance, is there a point on the trajectory where the sum of forces is 0? I don't think so, but maybe at ...
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1answer
206 views

Follow up question regarding: Deceleration rate of objects of different mass but the same otherwise

My first question was answered here: Deceleration rate of objects of different mass but the same otherwise . But based on that, here is a follow-up question (I also edited my first post with the ...
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1answer
2k views

A ball is thrown up, and a second ball is dropped- what is the maximum initial velocity of the first ball so that [closed]

This question only exists in one dimension, the y axis. A ball is thrown upwards with an initial velocity $V_o$ from a roof with height $h$. One second later, a second ball is dropped from the same ...
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2answers
1k views

Upthrust vs Drag

24: A ball is falling at terminal speed in still air. The forces acting on it are upthrust, viscous drag and weight. What is the order of increasing magnitude of these 3 forces? ...
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2answers
360 views

How jet engine works in vacuum

Its not about availability of oxygen for combustion of gases. I want to know since there is no air or friction providing things in vaccum, how the force applied by a jet engine get can make thrust to ...
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1answer
557 views

1D Motion under Gravity

I have attempted this question in so many different ways but I am getting nowhere. Could someone point me in the correct direction so I can work it out myself? Here is the question: An object $K$ ...
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2answers
1k 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 ...
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1answer
617 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 ...
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2answers
248 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 $D$. ...
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2answers
2k 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 ...
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1answer
5k views

Maximum range of a projectile (launched from an elevation)

If a projectile is launched at a speed $u$ from a height $H$ above the horizontal axis, and air resistance is ignored, the maximum range of the projectile is $R_{max}=\frac ug\sqrt{u^2+2gH}$, ...
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1answer
216 views

Is it theoretically possible for the orientation angle of a projectile to remain exactly equal to the orientation of velocity?

This question is sparked by my answer to this question: Is this simulation following real physics? After examining the math, I don't see how it is theoretically possible for the situation simulated ...
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2answers
4k views

Projectile motion without air resistance [closed]

Does the mass of projectile affect its trajectory when it is projected in no air resistance environment and why?
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2answers
48 views

Simple harmonic motion mass between 2 buildings

I have a question, where I have a mass on top of a building, we give it initial velocity of $\sqrt{gd/2}$ then it starts colliding between 2 buildings, elastic collision. I have to find how many times ...
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1answer
57 views

Projectile motion with air friction force/resistance [closed]

We have to find the x (the distance, if you didn't know that then I'm not sure if you should be doing this problem) that the projectile travel during the time in the air until the time it hits the ...
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1answer
48 views

Calculate final velocity for vertical projectile with air resistance

I am struggling to figure out how to calculate the final velocity of a projectile that is shot vertically upwards and then let fall down again to the starting point. I can easily calculate this in ...
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2answers
85 views

Somewhat unusual projectile motion question

A stone must fly over two walls of height $h_1$ and $h_2$ $(h_2~ > ~h_1)$ from the side of the lower wall. The distance between the upper points of the two walls near which the stone's trajectory ...
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1answer
181 views

A projectile is shot straight up from (non-rotating) Earth's surface at a speed of 10,000 km/h. How “high” does it go (to 2 s.f, in m)? [closed]

What is wrong with my work? It continuously gives me an incorrect error, but I can't identify the step at which I made a mistake. My work is shown as follows: let the height be h radius of earth , r ...