How long for 35kg mass to double speed with 55N force?

[Chris18]

Homework Statement

A body of mass 35kg moving with velocity Vox=40m/s is subjected to a constant Force of 55N acting in the same direction.How long does it take the speed to increase twice?

Homework Equations

I would be grateful if anyone could give me hand to solove it after i find the acceleration a= F/m...

The Attempt at a Solution

 

[haruspex]

I assume it means, how long does it take for the speed to double.
Are you familiar with the SUVAT equations?

 

[Chris18]

I am to the most of them... Still I don't know which one to use. Could you give me a hand here?

 

[haruspex]

I am to the most of them... Still I don't know which one to use. Could you give me a hand here?

In the usual form, there are five variables and five equations. Each equation involves a different four of the variables. Typically, you know three values and wish to find a fourth. So pick the equation involving those four.