Question

On planet Tehar, the free-fall acceleration is the same as that on Earth, but there is also a strong downward electric field that is uniform close to the planet's surface. A 1.86-kg ball having a charge of 5.04 μC is thrown upward at a speed of20.1 m/s. It hits the ground after an interval of 4.10 s. What is the potential difference between the starting point and the top point of the trajectory? (Use 9.8 m/s² for the acceleration due to gravity.)

Answer 1

To solve this problem you have to know about Electric Potential and Potential Energy

Step 1.

Definition:

Electric Potential: Is the amount of electric potential energy that a unitary point electric charge would have if located at any point in space, and is equal to the work done by an electric field in carrying a unit positive charge from infinity to that point.

Potential Energy: Potential energy is energy that results from the position or shape of the object. An object can have the ability to perform work as a result of its position in a gravitational field (gravitational potential energy), an electric field ( electric potential energy ), or a magnetic field (magnetic potential energy).

Step 2.

Apply the conservation of energy between the starting point and the top point, we have the following:

                                                    

In the starting point, height is zero there isn't potential energy and the top point the kinetic energy is zero because in the top point the velocity is zero.

                     

Now apply the equation of electric potential give by a point charge:

Now, do the potential in the starting point zero we will calculate the potential in the top point

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