The description of the movement of bodies by their position, velocity, acceleration (and possibly higher time derivatives, such as, jerk) without concern for the underlying dynamics/forces/causes.

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2
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0answers
23 views

What will be the time taken by a stone to reach the ground if it is thrown with velocity $v$? [on hold]

I was studying from my reference book and I got this question. I tried solving it by finding the total distance n average velocity but it didn't work please help me out.
0
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0answers
28 views

Kinematics/ Projectile Motion Lab [on hold]

This is a question from a projectile motion experiment. Using kinematics you will be asked to calculate the initial velocity of the projectile by measuring its vertical drop h, and the horizontal ...
0
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1answer
65 views

Kinematics is much more difficult than it should be

Just to clarify, this is not a homework problem. I'm using this for some code I'm writing for a simulation: I'm trying to find a point at which I should switch from a positive acceleration of a ...
0
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0answers
26 views

Finding the change of velocity [on hold]

What is the change in velocity when: a cricket ball strikes the pitch at a speed of 30 m s^-1 and an angle to the ground of 28 degrees and bounces up at an angle of 35 degrees and a speed of 25 m ...
1
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1answer
19 views

How to convert translational energy to rotational energy

Suppose that I have a body moving at certain velocity in straight line. So it has translational energy. I want to convert this energy to rotational energy of another body, by making the velocity of ...
0
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0answers
24 views

Kinematics - Projectile motion down an inclined plane

The inclined plane has angle A over the horizontal. A projectile is thrown down the inclined plane at angle B relative to the incline at velocity V. What is the time taken, range, and max ...
0
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0answers
24 views

Acceleration of Second Leg in One Dimensional Physics? [on hold]

Example: While you are sitting on a park bench with your friend, you grab his hat and start running in a straight line away from him. Over the first $24.2m$, you accelerate at $1.00m/s^2$ up to your ...
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0answers
32 views

Determining Average Velocity [on hold]

I was working on some practice average velocity problems and I came across this one: The position of an object as a function of time is given by $x(t)=(2.0m/s) t - (5.0m/s^2)t^2.$ What is the average ...
0
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1answer
19 views

Motion and acceleration in a straight line [on hold]

A car with an initial velocity of 3 m/s has a velocity of 34 m/s after 3 sec. How far it moves in its third second of motion? acceleration V=U + at a = 10.3 m/s^2 x = ut + 1/2 a t^2 x = 3 (3) ...
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0answers
14 views

At time $t=0$, what are the magnitude and direction of the perpendicular component of dp/dt? [on hold]

In the dark in outer space, you observe a glowing ball of known mass 4.6 kg moving in the xy plane at constant speed in a circle of radius 7 m, with the center of the circle at the origin (< 0, 0, ...
1
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0answers
20 views

Estimate the distance covered [on hold]

I know it says estimate, but how? If it's linear I could do something, but it's a curve and so inaccurate. My best try was this. 1000 * 100 = 100000 Which gives me the area of the rectangle which ...
0
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0answers
14 views

Kinematics problem - three masses, two tensions, kinetic friction, and a pulley [on hold]

I took a test in general physics yesterday that had the following kinematics problem: $\hskip 0.7in$ The 10kg body has downward acceleration $a=1.5\frac{m}{s^2}$ and there is a kinetic coefficient ...
-1
votes
1answer
15 views

What is the objects speed? [closed]

A magnetic field will deflect a charged particle perpendicular to its direction of motion. An electron experiences a radial acceleration of 8.60E+14 m/s^2 in one such field. What is its speed ...
1
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0answers
23 views

2D Kinematics cliff problem [closed]

I'm having trouble with a kinematics problem... "A potato gun is fired up at a 50 degree angle off a 35 meter cliff. If it landed 7.5 seconds later, how far away from the base of the cliff ...
9
votes
3answers
1k views

Is it possible to have a rate of change of acceleration?

I know this may seem a weird question, but it always bothers me. My physics book (Resnick,Halliday,Walker), and also various sites never say anything beyond acceleration. But when a moving body is ...
0
votes
1answer
37 views

Why does the expression for this object's velocity have -T in it? [closed]

The original question: At $t = 0$, an object of mass $m$ is at rest and at $x = 0$ on a horizontal, frictionless surface. A force in the $x$ direction: $$ F(t) = F(0) e ^{-t/T} $$ is ...
0
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0answers
14 views

how do I resolve this velocity into components? [closed]

my problem is: And this is the diagram I drew to resolve it into its constituent R and theta forces: So I get \begin{align} V_r &= - V \cos \theta \\ V_\theta &= V \sin \theta ...
2
votes
0answers
30 views

What does kinetic energy at infinity mean in terms of supernovae?

I have noticed that in some paper that the term "kinetic energy at infinity" is used. I understand what potential energy with reference to infinity mean, but what does the term kinetic energy of ...
1
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2answers
43 views

Derivation of the average Velocity formula with constant acceleration (using calculus)

I have been looking at $$ v_{avg} = \frac{v_{i} + v_{f}}{2}, $$ when the acceleration is constant, where $v_i$ is equal to the initial velocity and $v_f$ is equal to the final velocity. How can ...
0
votes
2answers
66 views

Free fall and projectile motion

I'm wondering if something is falling say from a roof, would the distance it falls be the final $y$ position? Also would all the $y$ components (velocity, displacement) be negative?
1
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1answer
19 views

Speed with wind resistance

This is probably a basic question, but it has been a while since I did anything like this. If a boat is sailing forward at speed $x$ and the direction of the wind, with magnitude $y$, is either equal, ...
1
vote
1answer
33 views

A ball is dropped from the roof of a building. How fast is it moving after 4.9 seconds? (Absolute value) [closed]

i really need help. A ball is dropped from the roof of a building. How fast is it moving after 4.9 seconds? (Absolute value) in m/s A water balloon is thrown downward from a tall building with an ...
0
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0answers
13 views

Help with Kinematics and trajectory [duplicate]

I am asking this again because it was closed and I didn't receive a response. So a baseball is hit with a velocity of 30 m/s at 42.6 degrees to the ground. A fielder who is supposed to catch the ...
0
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0answers
10 views

Projectile motion help needed [duplicate]

I have a question. So a baseball is hit with a velocity of 30 m/s at 42.6 degrees to the ground. A fielder who is supposed to catch the ball is smart and knows that he is exactly 8 meters from where ...
0
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0answers
20 views

Two Dimensional Kinematics and Projectile motion [duplicate]

I have a question. So a baseball is hit with a velocity of 30 m/s at 42.6 degrees to the ground. A fielder who is supposed to catch the ball is smart and knows that he is exactly 8 meters from where ...
1
vote
1answer
49 views

Path of wheels of a bicycle

Why are the wheels of a bicycle moving in concentric circles with the center O? I know that the velocity of the back wheel is parallel to the frame of the bicycle and the velocity of the front wheel ...
1
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1answer
78 views

A question about finding average velocity and average acceleration

I have trouble understanding the following problem's answer: Which of the following relations are true for any arbitrary motion in space? (a) $v_{avg}=\frac{r(t_2)-r(t_1)}{t_2-t_1}$ ...
0
votes
1answer
30 views

Horizontal distance covered by an object from an initial height to the ground

We are given: An angle $\theta$ with respect to the ground, its initial height $h_0$ and the final distance $d$. How can we find the initial velocity from this information? I tried a bunch of things, ...
-1
votes
1answer
49 views

Direction of radial acceleration same in circular motion?

I have a big confusion. There is a question in my book which basically says that a ball is tied to a string and rotated. and it asks me to tell whether the following statement is true of false. ...
3
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0answers
65 views

Acceleration: A ball sliding down the inside of a semicircular bowl

Edit: To clarify, this is a homework question. But I couldn't care less about getting the answer to this specific question as it's not even assigned yet. It looks interesting and I want to understand ...
0
votes
1answer
58 views

Finding resultant and direction of resultant

In this question- A motorboat is racing towards north at 25km/h and the water current in that region is 10km/hr in the direction of 60 degree east of south. Find the resultant velocity of the ...
1
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1answer
43 views

How to use accelaration data of moving object to calculate distance?

I read couple of similar question on this forum and few blogs on web, though I am still confused,I am determined to calculate object displacement using accelerometer data. So, I tried using ...
0
votes
2answers
32 views

Is in this case distance same as displacement? [closed]

I have this graph, and I need to know the displacement in the interval from 0 to 5 seconds, so I found the area of the rectangle that you can see there. A = w*h, which means X = (5 seconds)*(20 m/s), ...
-1
votes
1answer
38 views

A particle has $\overrightarrow{r}(0)=4m(\hspace{2pt}\hat{j}\hspace{2pt})$ and $\overrightarrow{v}(0)=(2m/s^2)\hat{i}$ [closed]

I am having trouble with these problems, and I want to gain a understanding of how to solve these. I'll put what I have tried at the end, even though I don't think it'll be of help. A particle has ...
1
vote
2answers
40 views

Projectiles Launched at an Angle with unspecified Initial Velocity [closed]

I'm attempting to do my Physics homework, and I did the first one right, but that problem gave me initial velocity. This problem gives me only the angle relative to horizontal and the distance it ...
2
votes
1answer
32 views

Viscosity and Density

So I'm reading my textbook and it says that that magnitude of air resistance $f(v)$ can be given as a taylor expansion: $$f(v) = bv + c^2v = f_{\text{linear}} + f_{\text{quadratic}}$$ The linear ...
1
vote
0answers
56 views

Projectile Motion Equation - Understanding this Formula [closed]

I don't understand why this formula is relevant to the problem: This was the relevant worked solution: My problem is that I do not understand this formula because I don't even understand what ...
0
votes
2answers
39 views

What is the percentage of energy recovery in Kinetic Energy Recovery Systems(KERS) in cars?

Kinetic Energy Recovery Systems (KERS) use flywheels to recover energy from the kinetic motion of cars. They use a rotating flywheel that generates energy as it rotates- this generates the electric ...
0
votes
2answers
60 views

A problem says : a car starts from rest and undergoes a constant acceleration. It travels 5 m in the…? [closed]

A problem says : A car starts from rest and undergoes a constant acceleration. It travels 5 m in the t interval 0 s to 1 s, find the displacement of the car during the time interval from 1 s to 2 ...
-1
votes
3answers
66 views

Question on acceleration of gravity

In pre-calculus last week my teacher explained a scenario in which a man throws a rock down a well and takes 4 seconds for you to hear the rock hit the bottom. How far downs the well? Last years I ...
-1
votes
1answer
43 views

How do you find the average speed and average velocity? [closed]

The shuttle craft "Galileo" travels at a constant velocity of $2.73*10^3$ m/s up for $34.0$ min. and then turns around to travel $1.45*10^3$ m/s down for $15.0$ min. a) Find its average speed. b) ...
-5
votes
1answer
40 views

About how much force would something have to exert to be effectively unstoppable? [closed]

Assuming an object is moving in a straight line propelled by a force. How much energy would that force have to exert so that there are no known forces or objects that could stop it from moving in that ...
5
votes
1answer
35 views

How to calculate the kinetic energy of supernova ejecta?

I believed I could use $0.5\times M_{ej} V_{ej}^2$, with $M_{ej}$ being the ejected mass and $V_{ej}$ being the velocity of the ejected mass. But I noticed in this and this that the the mean velocity ...
0
votes
1answer
38 views

Ways of finding average accelleration

So I had a little debate with a professor on a simple problem of motion (See section). It basically comes down to how to find average acceleration. I did some research and couldn't find a definite ...
0
votes
1answer
37 views

Average acceleration when more than two different velocities occur [closed]

Suppose a car travels at 5m/s north for 5 seconds, it then turn east and travel at 7m/s for 10 seconds, finally it turns north east and travel at 10 m/s for 20 seconds. What is the average ...
0
votes
1answer
31 views

Finding Acceleration Force of Gravity on Rotated Accelerometer

Is it possible to calculate the force of gravity on the $x$, $y$, and $z$ readings of an accelerometer if I know the rotation of the sensor? If so, how would I do this? Sorry if I am doing this ...
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vote
3answers
184 views

Two runners on two different tracks

I got a question from a textbook, as follows. On two different tracks, the winners of the one-kilometer race ran their races in 147.95 seconds and 148.15 seconds. In order to conclude that the ...
0
votes
2answers
40 views

Problem finding the average velocity [closed]

Problem: A car travels along a straight line for first half time with speed of 40 km/h and second half time with speed 60 km/h. The mean speed of the car is__________. My answer: 48 km/h Why? ...
1
vote
1answer
75 views

Relative velocity of two cars [closed]

Two cars A and B are at $100\,\text{m}$ and $200\,\text{m}$ distance from the origin $O$ at time $t = 0$. They start simultaneously with velocities $10\,\text{m/s}$ and $5\,\text{m/s}$ respectively. ...
1
vote
1answer
33 views

Gravitational Potential Energy to Kinetic Energy

When a yo-yo is released from a height $h$, the gravitational potential energy is converted to kinetic energy. However, the yo-yo obviously has less acceleration than $g$, $9.8\frac{m}{s}$. This means ...