Tagged Questions
0
votes
1answer
44 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
2answers
90 views
Doubt in Kinematics
I know that this isn't the place for such basic questions, but I didn't find the answer to this anywhere else. It's pretty simple: some particle moves in straight line under constant acceleration from ...
2
votes
1answer
138 views
Calculate displacement in position from knowing constant acceleration
I have recently started studying physics at school, and my teacher went over the following equation without explaining about it too much:
$$d~=~vt+\frac{1}{2}a t^2.$$
I have wondered, why would this ...
0
votes
2answers
139 views
Equation of motion for average acceleration
I am trying to solve the following:
A man of mass 83 kg jumps down to a concrete patio from a window ledge only 0.48 m above the ground. He neglects to bend his knees on landing, so that his ...
0
votes
0answers
54 views
At an acceleration of 2ft/s^2, how fast could I reach 9.8MPH? [closed]
Question title is self explanatory.
If I'm accelerating at $2ft/s ^{2}$, how long does it take to reach $9.8MPH$?
0
votes
1answer
96 views
What's the difference between these two formulas and how are these called?
I just want to know the differences between these two formulas:
$h = h_0 + v_0 t ± \frac{1}{2} g t^2$
and
$y = y_0 + v_{0y} t + \frac{1}{2} g t^2$
Also, how are these called in English?
1
vote
1answer
140 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 ...
0
votes
0answers
54 views
Accelerated motions of a car and a truck [closed]
A car and a truck start from rest at the same instant with the car initially at same distance behind the truck. The truck has constant acceleration of 3.4 m/s^2. The car overtakes the truck within the ...
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 ...
2
votes
2answers
386 views
How do I find minimum constant deceleration so that object does not pass distance d in time t?
I'm working on a problem for an online judge site. I've boiled down the problem to this calculation: given a vehicle with an initial velocity $v$, how can one calculate the minimum constant ...
3
votes
1answer
300 views
How do I find the initial velocity in this problem?
An X-ray tube gives electrons constant acceleration over a distance of $20\text{ cm}$. If their final speed is $2.0\times 10^7\text{ m/s}$, what are the electrons' acceleration?
I know this ...
0
votes
0answers
226 views
Calculating the time given initial position, initial velocity, current position and constant acceleration [closed]
I'm trying to write a simple physics engine (a bit different than what is already out there) and I've got the following problem;
(For simplicity let's imagine this problem in one dimension;)
I have ...
-2
votes
1answer
404 views
Calculate acceleration and time given initial speed, final speed, and travelling distance? [closed]
A motorcycle is known to accelerate from rest to 190km/h in 402m.
Considering the rate of acceleration is constant, how should I go about calculating the acceleration rate and the time it took the ...
0
votes
2answers
88 views
Proof of $T=\sqrt{2y/a}$ in uniformaly accelerating object [closed]
Suppose that there is a object that does a y-axis-only free fall to ground. The initial distance from the ground is defined as $H$.
How does one prove that time the object takes to reach the ground ...
0
votes
0answers
149 views
Basic Kinematics Question [closed]
I have a pretty basic problem regarding kinematics, but I'm new to physics. So, I'm having trouble with it. No, it is not homework. These are review problems, but this particular one is troubling me.
...
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:
...
0
votes
0answers
74 views
Jumping on a landing pad [closed]
I'm trying to make a character jump on a landing pad who stays above him. Here is the formula I've used (everything is pretty much self-explainable, maybe except character_MaxForce that is the total ...
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 ...
0
votes
2answers
820 views
How do you calculate angle of projection?
At what angle the projectile should throw with initial velocity v in order to reach distance d? discard the air resistance, only gravitation acts. So far I got the equations for horizontal and ...
-1
votes
1answer
1k views
Question on Projectile Motion equation [closed]
A golf ball is shot into the air from the ground. If the initial
horizontal velocity is 20m/s and the initial vertical velocity is
30m/s, what is the horizontal distance the ball will travel ...
3
votes
3answers
361 views
A freefalling body problem, only partial distance and time known
Well, I've been trying to figure out a problem which I imposed on myself, so no literal values included. Unfortunately, my brain is not cooperating.
The problem states:
What is the height from ...
-1
votes
1answer
369 views
The acceleration of a particle moving only on a horizontal plane is given by a= 3ti +4tj, [closed]
The acceleration of a particle moving only on a horizontal plane is given by a= 3ti +4tj, where a is in meters per second-squared and t is in seconds.
At t = 0s, the position vector r= (20.0 m)i + ...
1
vote
2answers
74 views
Acceleration: Value Disparity?
If we consider a ball moving at an acceleration of $5ms^{-2}$, over a time of 4 seconds, the distance covered by the ball in the first second is $5m$. In the 2nd second will $5 + 5 = 10m$. In the ...
0
votes
2answers
775 views
What do I need to do to find the stopping time of a decelerating car? [closed]
The question is:
A car can be stopped from initial velocity 84 km/h to rest in 55 meters. Assuming constant acceleration, find the stopping time.
Sorry for my ignorance, but I need to review ...
0
votes
2answers
177 views
Why wouldn't this system of equations determine where two balls meet?
A ball is thrown vertically upwards at $5\text{ m/s}$ from a roof top of $100\text{ m}$. The ball B is thrown down from the same point $2\text{ s}$ later at $20\text{ m/s}$. Where and when will ...
0
votes
1answer
122 views
I think I disprove this with kinematics, but energy says it is right
!
Here is my kinematics argument. For now I am only going to look at ball 2 and ball 3. Make note of the following data.
$|v_0| = 10m/s$, $y_0 = 10m$, $\theta_2^0 = 30^0$, $\theta_3^0 = -45^0, g = ...
1
vote
2answers
212 views
Using acceleration to plot position
Sorry if this question is dumb, and I know is physics 101, but I'm not that good with physics.
I'm writing an iPhone program that by collecting the acceleration data of the device tries to replicate ...
0
votes
3answers
581 views
Very basic question: When to use $s=vt$, $s=1/2vt$, $s=at$ and $s=a/t^2$?
Very basic question: When to use $s=vt$, $s=\frac{1}{2}vt$, $s=at$ and $s=\frac{a}{t^2}$?
What was the difference between those?
