Given constant speed this question so speed are same... this moved on straight line also velocity are same in same direction

Explanation:

When an observer moves with a constant speed along the line joining two stationary objects, he will observe certain characteristics about the motion of these objects. Let's discuss each option and explain why it is correct.

a) Have the same speed:
When the observer moves with a constant speed, he will perceive the speed of the objects to be the same. This is because the observer is moving with a constant speed and is not accelerating. Therefore, the relative speed between the observer and the objects remains constant. Since the objects are stationary, the observer will perceive them to have the same speed as his own.

b) Have the same velocity:
Velocity is a vector quantity that includes both magnitude (speed) and direction. Since the observer is moving along the line joining the two objects, he will perceive the objects to have the same velocity. This is because the direction of the observer's motion and the direction of the objects' positions are the same. Although the objects may have different speeds, their velocities will be the same as long as they are moving in the same direction.

c) Move in the same direction:
As mentioned earlier, the observer is moving along the line joining the two objects. Therefore, he will perceive the objects to be moving in the same direction as himself. This is because the observer's motion sets the frame of reference, and any objects that are stationary in this frame will appear to move in the same direction as the observer.

d) Move in opposite directions:
This option is not correct. Since the observer is moving with a constant speed along the line joining the two objects, he will not perceive them to be moving in opposite directions. In order for the objects to appear to move in opposite directions, the observer would need to change his direction of motion or accelerate. However, in this scenario, the observer maintains a constant speed and moves in the same direction as the objects.

In conclusion, when an observer moves with a constant speed along the line joining two stationary objects, he will observe that the objects have the same speed, the same velocity, and move in the same direction.