Kinematic equation problems(HELP ME)

[aprilgraceamo]

Homework Statement

An arresting device on a carrier deck stops an airplane in 1.5s. The average acceleration was 49 m/s^2. What was the stopping distance? What was the initial speed?

Homework Equations

?


3. The Attempt at a Solution [/b

DONE! :D
No need for help anymore :D

 

[Yanick]

Do you know your kinematic equations? Typically I try to actually reason out Physics problems (really understand why something is negative or positive or increasing etc) as this truly helps you to learn the material. However, if you are stuck on a question which actually counts toward your grade then the best way that I've found was to write all known data (not all that data will be explicitly stated, half of classical mechanics is being able to get that one key piece of information based on the data given to you) then write out all equations, plug everything in, see what you can solve for, rearrange equations etc. Basically just solve for everything mathematically and sooner or later you will get the variable they are looking for.

So just to give you a place to start. It sounds like a 1D motion problem (I'm picturing the airplane already on the carrier when it hits the stopping mechanism), so its going to be pretty basic.

What information do you know from the problem?
t(time) = 1.5s as an example.

What other info can you glean from the problem statement? Don't forget about setting up your reference frame so your signs will work out properly (this is a deceleration problem so some things will be negative and others will be zero).

This problem can be done with these two equations:
Vf=Vi + at
Xf=Xi + Vi*t + 1/2at^2

Once again look at the problem, see what data you have (both explicitly stated and implied under the circumstances), make sure your reference frame is set up properly to 1-make some of the math easier and 2-to make sure your signs are consisten. And go ahead and post up your attempt.

 

[aprilgraceamo]

I'm already done with this one. Got an answer for it already. I was just confused about the signs and the what equation to use. But done already. Thanks for the info :D

 

[aprilgraceamo]

Homework Statement

An arresting device on a carrier deck stops an airplane in 1.5s. The average acceleration was 49 m/s^2. What was the stopping distance? What was the initial speed?

Homework Equations

?

The Attempt at a Solution

Please give me some :(((

Homework Statement

Homework Equations

 

[paranormal]

I would like to provide a response to the above content. Firstly, kinematic equations are mathematical formulas that describe the motion of objects. They are commonly used in physics to solve problems related to motion and acceleration.

In this particular problem, we are given information about an airplane being stopped by an arresting device on a carrier deck. We are asked to find the stopping distance and the initial speed of the airplane.

To solve this problem, we can use the following kinematic equation:

v^2 = u^2 + 2as

Where:
v = final velocity (which is 0 m/s since the airplane comes to a stop)
u = initial velocity (what we are looking for)
a = average acceleration (given in the problem)
s = stopping distance (what we are looking for)

Substituting the given values, we get:

0^2 = u^2 + 2(49)(s)

Simplifying, we get:

u^2 = -98s

Now, we can use the fact that the airplane comes to a stop in 1.5 seconds, so the total time is 1.5 seconds.

We can use the following kinematic equation to find the initial velocity:

v = u + at

Where:
v = final velocity (0 m/s)
u = initial velocity (what we are looking for)
a = average acceleration (given in the problem)
t = time (1.5 seconds)

Substituting the values, we get:

0 = u + (49)(1.5)

Solving for u, we get:

u = -73.5 m/s

This means that the initial speed of the airplane was 73.5 m/s before it was stopped by the arresting device.

To find the stopping distance, we can substitute the value of u into the first equation we used:

0^2 = (-73.5)^2 + 2(49)(s)

Simplifying, we get:

-1071 = 98s

Thus, the stopping distance of the airplane is approximately 10.92 meters.

In conclusion, by using the appropriate kinematic equations, we were able to solve for the initial speed and stopping distance of the airplane in this problem. It is important to note that these equations can be used in a variety of situations to solve problems related to motion and acceleration.