While riding trax at a constant speed of 16 m/s you walk toward the front of the car at 5 m/s. what is your velocity relative to someone standing outside the train?: )

Speed of the TRAX is given as 16 m/s so let say it is given as

now our speed towards the front end is given by 5 m/s so this is the relative speed of us with respect to TRAX

let say this speed is given as

now we need to find the speed with respect to someone standing outside the TRAX

so here we need to find the net speed in ground frame and hence we can use the formula of relative speed

so someone outside the TRAX will see our speed as 21 m/s

probably not if net force is zero

i believe the answer would be:

d. violin, clarinet, french horn, and tuba