4. two straight wires are parallel and carry currents of 1.2 a in opposite directions, as shown. find the direction of the magnetic field produced by the current in wire 1 at the location of wire 2 and mark the direction directly on your printed diagram using the direction symbols indicated. label the symbol for the field direction b. then find the direction of the magnetic force on wire 2, mark it with the appropriate one of the direction symbols and label the force direction f. finally, explain how your answer for the magnetic field and magnetic force would have changed if the current in wire 1 had been reversed, but the current in wire 2 remained the same, so that both currents were in the same direction.

The directions of magnetic force and magnetic field lines are shown in the figure.

The direction to find out the magnetic field lines is given by right hand curl rule. If the thumb shows the direction of current, then the curling fingers show the direction of magnetic field lines.

The direction of force can be given by right hand thumb rule, where

Thumb - Direction of magnetic field lines
Forefinger - Magnetic force
Centre finger - Current  

Such that forefinger, centre finger and thumb must be at 90 degrees to each other.

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction