Mechanical energy is conserved in the presence of which of the following types of forces?

PSS 21.1 Conservation of energy in charge interactions 

Learning Goal: 

To practice Problem-Solving Strategy 21.1 Conservation of energy in charge interactions. 

An alpha particle (a), which is the same as a helium -4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of -3.45 × 10^-3 V.

The charge and the mass of an alpha particle are q_a= 3.20 × 10^-19 C and m_a = 6.68 × 10^-27 kg respectively.

Prepare

Identify the system involving the alpha particle. Then examine the forces acting within this sy whether mechanical energy is conserved. Make certain to draw a before-and-after visual ove symbols. 

Part A 

Mechanical energy is conserved in the presence of which of the following types of forces 

Select all that apply. 

1, frictional 

2, magnetic 

3, electrostatic 

4, gravitational