Question

An electron is initially moving at 1.4 x 107 m/s. It moves 3.5 m in the direction of a uniform electric field of magnitude 120 N/C. What is the kinetic energy of the electron at the end of the motion

Answer 1

The kinetic energy of the electron at the end of the motion is 1.79 x 10^-13 Joules.

Step-by-step explanation:

To calculate the kinetic energy of the electron, we can use the equation:

Kinetic Energy = 0.5 × mass × velocity2

Given that the initial velocity of the electron is 1.4 x 107 m/s and the distance it moves is 3.5 m, we can calculate the final velocity as follows:

Final velocity = Initial velocity + (Acceleration x Time)

Since the electric field is uniform, the acceleration can be calculated using the equation:

Acceleration = Electric Field Strength

Then, the time can be calculated using the equation:

Time = Distance / Final velocity

Plugging in the values and calculating, we find that the final velocity is 1.96 x 107 m/s. Now, substituting the values into the kinetic energy equation, we get:

Kinetic Energy = 0.5 × mass × velocity2

Kinetic Energy = 0.5 × (9.11 x 10-31 kg) × (1.96 x 107 m/s)2

Kinetic Energy = 1.79 x 10-13 Joules