Question

A moving electron has kinetic energy K1. After a net amount of work W has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) FindW in terms of K1

Answer 1

Answer:

15/16 k₁

Explanation:

k₁= 1/2 mv₁² is where k₁ is the kinetic energy of the electron before the work is done

K₂ = 1/2 m(-v₂)² after the work has been done

also given

v₂ = - v₁ / 4

substitute v₂  into the formula for K₂

k₂ = 1/2m (  - v₁ / 4)²

k₂ = 1/2mv₁²/16 = 1/16 k₁

work done on the electron according to work- energy theorem is equal to the change in the kinetic energy of  the electron

• W = k₂ - k₁ = 1/16 k₁ -  k₁  = -15/16 k₁

Answer 2

The value of W in terms of K1 is 15/16 k1

What is Kinetic energy?

This is the energy possessed by a body by virtue of its motion or movement.

The formula is given below:

k1= 1/2 mv₁² (before work was done)

K2 = 1/2 m(-v₂)² (after work was done)

Since we were given v₂ = - v₁ / 4 we can substitute for K2:

Substitute v₂ into the formula for K2

k2 = 1/2m ( - v₁ / 4)²

k2= 1/2mv₁²/16

= 1/16 k1

Work done on the electron according to work minus energy theorem = change in kinetic energy

W = k2 - k1 = 1/16 k1 -  k1

= -15/16 k1

Read more about Kinetic energy here https://brainly.com/question/8101588