All Questions
31 questions
-1
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1
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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 ...
- 3
0
votes
2
answers
49
views
Equations of motion for constant acceleration
I read that the equations of motion for a constant acceleration can be represented in a scalar form as well as a vector form, but what's the need to do them in vector form what extra can we do by ...
- 51
0
votes
1
answer
83
views
${}$ Projectile motion
Basically we take the value of acceleration due to gravity as -ve ($-g$),when an object is thrown in the opposite direction of $g$. But in projectile motion the object first opposed the g and travels ...
user379270
2
votes
1
answer
786
views
How can I calculate the intercept direction of a constant accelerating missile?
I'm simulating missiles in 3d space and want the missiles to intercept a target which has constant velocity.
Given the targets velocity is "u" a vector and the missiles acceleration rate is &...
- 21
1
vote
1
answer
143
views
How to know which solution is physical?
When solving the expression for displacement of an accelerating object and solving for the time variable:
$$v_it+\frac{1}{2}at^2=d$$
$$v_it+\frac{1}{2}at^2-d=0$$
$$t=\frac{-v_i\pm \sqrt{v^2_i+2ad}}{a}$...
user324326
1
vote
1
answer
38
views
What numbers would I apply to the equation $y=y_o+v_ot+\frac 12at^2$ using this simulator?
Using a Projectile Motion Simulutator (selecting INTRO from the four choices), I set the height of the Cannon at $15 \ \text{m}$, Initial Speed = $8 \ \text{m/s}$, the bulls-eye at $13.9 \ \text{m}$. ...
- 111
2
votes
7
answers
4k
views
The direction of the velocity of a body can change when its acceleration is constant. How is it possible since acceleration is a vector quantity?
As we already know that acceleration is a vector quantity which means that it has both direction as well as magnitude. It can also change given any one of the two or both (magnitude and direction) ...
1
vote
5
answers
5k
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Why is the acceleration along $x$-axis during projectile motion equal to 0?
Why is the acceleration along x axis during projectile motion equal to $0$?
And if it is equal to $0$ then the object shouldn't stop along x-axis after vertical velocity reaches $0$ along $y$-axis.
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-2
votes
2
answers
53
views
Projection of ball. find initial velocity [closed]
A cannonball is fired at an angle of 33 degree relative to the horizontal as shown in the figure bellow.
It is 1930 meters in the horizontal direction from the point of launch to the point where the ...
-6
votes
4
answers
676
views
Motion in a straight line [duplicate]
Velocity and acceleration are directly proportional to each other but in the case of throwing a ball up , at the top velocity is zero but acceleration is there. why?
0
votes
7
answers
404
views
Vertical motion of an object
We define acceleration as $-9.8\frac{m}{s^2}$ for an object that is thrown upwards due to gravity. My question is when the object reaches maximum height at the point where it is about to turn around ...
- 23
1
vote
4
answers
2k
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How can there be acceleration but no velocity at instant of maximum height when object projected upwards? [duplicate]
When we project an object vertically upwards its velocity at maximum height consider to be zero but still, it has acceleration due to gravity i.e $9.8\mathrm{m/s^2}$. But mathematically we know that ...
- 49
0
votes
2
answers
5k
views
Why is Speed of an object equal to square root of distance traveled multiplied square root of acceleration?
I wanted to find the relationship of the speed of a falling object in a vacuum at g=9.8 m/s2 compared to its distance. I wanted to get time out of the equation. When I plotted the relationship it ...
- 247
1
vote
1
answer
48
views
Calculating a free fall vector so its equals to its inverse vector while accounting for gravity
I'm a game developer, and I've been struggling with a kinematics problem in the development process of my current project.
I have some stationary objects that are suddenly affected by gravity after a ...
- 13
0
votes
3
answers
139
views
Should not the acceleration acting on the stone being dropped be $a$ as well along with $g$?
the question is:
A stone is released from an elevator going up with an acceleration a. The acceleration of the stone after the release is
(a) a upward
(b) (g-a) upward
(c) (g-a) downward
(d) g ...
- 185
1
vote
2
answers
129
views
How do you correctly apply $a=v\cdot\text dv/\text ds$? [closed]
I know that $a=v\cdot\text dv/\text ds$ can be deduced by simple algebra and calculus and is correct.
But once I was analyzing the motion of a ball projected straight up in free gravity. If I apply $...
-1
votes
1
answer
238
views
Use of direction of downward velocity in equation of motion
[NOTE: I am not asking anyone to solve the question below but to point out where I might be wrong]
Q- A skier jumps from a horizontal track and lands on a steeper track with a launch angle of ∅=11.3°(...
0
votes
2
answers
734
views
Confusion on Horizontal & Vertical Components of a Parabolic Motion
This was a question I found about projectile motion, the question was what's the bike's speed when it took off.
Using $S=ut + 0.5at^2$, the time taken to reach the ground is $0.505 s$, they used ...
- 1
1
vote
3
answers
410
views
Can average acceleration be exactly determined from discrete points separated by equal time intervals? [duplicate]
I am using the American dialect of the English language. The following definitions distinguish my question from the similar, previously asked question:
https://ahdictionary.com/word/search.html?q=...
- 2,052
-2
votes
1
answer
519
views
2-D motion Question [closed]
A bottle dropped from a balloon reaches the ground in 20 s. Determine the height of the
balloon if (a) it was at rest in the air and (b) it was rising with a speed of 50 m/s when the
bottle was ...
-1
votes
1
answer
55
views
-16 represents acceleration?
A physics teacher put a ball at the top of a ramp and let it roll down toward the floor. The class determined that the height of the ball could be represented by the equation, $h=-16t^2+4$, where the ...
J. Rosenberg
0
votes
3
answers
2k
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Does a ball, when thrown into the air, ever experience an instant of rest? [duplicate]
Say I walk outside and throw a ball into the air. Obviously it will decelerate as it travels upward due to Earth's gravity, and accelerate as it travels downward for the same reason. But is the ball ...
- 163
0
votes
1
answer
134
views
Direction of $g$ acceleration ball projection
Why is the answer A? Because I thought it's C, because g acts downward and since the ball is moving downwards towards N, acceleration should be "g" and not "-g" as it was when it was being thrown up ...
1
vote
3
answers
149
views
Projectile Motion - $V_f = V_i + at$ - Divide by zero
If I have a projectile that is thrown at some horizontal velocity at some height, and horizontal acceleration is zero, can't I use the equation $v = v_0 + at$? The problem is when I use it since $v$ ...
- 113
24
votes
7
answers
10k
views
Can an object *immediately* start moving at a high velocity?
What I mean is, suppose a ball is fired from a cannon. Suppose the ball is moving at 100 m/s in the first second. Would the ball have started from 1m/s to 2m/s and gradually arrived at 100m/s? And is ...
- 389
-6
votes
2
answers
4k
views
How to calculate initial acceleration of a projectile motion? [closed]
I have an object following a projectile motion, that hasn't got horizontal acceleration but only vertical -g.
What is the acceleration that I have to use in the second law of motion (F = ma) in order ...
- 111
0
votes
4
answers
5k
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 ...
1
vote
1
answer
59
views
Find the height and the velocity of the object [closed]
A bolt is detached from the lower part of an elevator cabin that is ascending with velocity 6meters/second and for 3 seconds comes to the point from where the elevator started to ascend. Find:
in ...
- 27
2
votes
9
answers
111k
views
Why isn't the acceleration at the top point of a ball’s journey zero?
When I shoot a ball vertically upward, its velocity is decreasing since there is a downward acceleration of about $9.8\,\mathrm{ms}^{-2}$.
I have read that at the top most point, when $v = 0$, the ...
- 1,790
2
votes
2
answers
6k
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 ...
0
votes
3
answers
10k
views
In a 2D problem with a thrown object, why is the acceleration along the x-axis equal to 0?
I'm starting Physics, and I don't understand why the acceleration along the x-axis is zero for an object thrown near the surface of the Earth. This may be problem specific, but I wouldn't know since I ...
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