Electric Field and Kinematic Equations for Acceleration and Time Calculations

In summary, the problem involves using the formula a= qe/ma to calculate the acceleration, and then substituting it into the kinematic equation x= vit + 1/2t^2. After solving for t, taking the initial velocity as zero, the resulting answer is 2.38 x 10^6 seconds. However, this is considered unreasonable as it is equivalent to 280 days. The same approach was used for part (b), but with a different kinematic equation vf= vi + at. The resulting answer for this part is -1.25 x 10^21 m/s, which is also deemed unreasonable as it is 11 orders of magnitude higher than the speed of light. It is suggested
  • #1
khuliso

Homework Statement



upload_2017-10-26_1-6-59.png

Homework Equations


F=qe, a= qe/ma, x= vit + 1/2t^2

The Attempt at a Solution


(a) i used the formula a= qe/ma to calculate the acceleration and then substituted in this kinematic equation x= vit + 1/2t^2 then i solved for t taking the initial velocity as zero.
(b) i used the same thinking but using the kinematic equation vf= vi + at

so i wanted to know if i have done the problem correctly , if i am wrong please give me a clue on how to approach this kind of problems
 

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  • #2

Homework Statement


upload_2017-10-26_1-21-15.png

-e = -1.9x10^-19 c , me= 9.1x10^-31 kg

Homework Equations


F=qe, a= qe/ma, x= vit + 1/2t^2

The Attempt at a Solution


(a) i used the formula a= qe/ma to calculate the acceleration and then substituted in this kinematic equation x= vit + 1/2t^2 then i solved for t taking the initial velocity as zero.
(b) i used the same thinking but using the kinematic equation vf= vi + at

so i wanted to know if i have done the problem correctly , if i am wrong please give me a clue on how to approach this kind of problems
 

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  • #3
We cannot tell you if you have done the problem correctly if you don't tell us what answer you got.
 
  • #4
number (a) my answer is 2.38 x 10^6 s
(b) my answer is -1.25 x 10^21 m/s
 
  • #5
khuliso said:
number (a) my answer is 2.38 x 10^6 s
(b) my answer is -1.25 x 10^21 m/s
(a) This is about 280 days. Without doing the calculation, I think this is unreasonable.
(b) The speed is 11 orders of magnitude higher than the speed of light. I think this is also unreasonable.

Please show the details of your calculation and how you got these numbers. Then someone should be able to point out where you went wrong. It's also possible that when you write it out for posting, you will pinpoint where you went wrong by yourself. It happens sometimes.
 
  • #6
How are we going to know if you did it correctly if you do not show us exactly what you did and tell us what results you got?

khuliso said:
x= vit + 1/2t^2
This is incorrect. I would suspect a typo, but you have written it in the same way twice. Make sure you get the relation correctly.
 

1. What is an electric field?

An electric field is a physical field that surrounds an electrically charged particle or group of particles. It is a vector field, meaning it has both magnitude and direction, and is responsible for the electric force experienced by other charged particles in its vicinity.

2. How is the electric field calculated?

The electric field is calculated by dividing the force experienced by a charged particle by the magnitude of the charge. It is represented by the equation E = F/q, where E is the electric field, F is the force, and q is the charge.

3. How does an electric field affect the motion of a charged particle?

An electric field can exert a force on a charged particle, causing it to accelerate in the direction of the field. The strength of the electric field and the magnitude of the charge will determine the acceleration of the particle.

4. What are the kinematic equations for acceleration and time calculations?

The kinematic equations for acceleration and time calculations are:

- v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time.

- s = ut + 1/2at^2, where s is the displacement, u is the initial velocity, a is the acceleration, and t is the time.

- v^2 = u^2 + 2as, where v is the final velocity, u is the initial velocity, a is the acceleration, and s is the displacement.

- a = (v-u)/t, where a is the acceleration, v is the final velocity, u is the initial velocity, and t is the time.

5. How are these equations used in real-life situations?

These equations are used in a wide range of real-life situations, from calculating the motion of a charged particle in an electric field to predicting the trajectory of a projectile. They are also used in engineering and physics to design and analyze various systems and machines, such as cars, airplanes, and roller coasters.

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