It is B since they are traveling at the same speed one is positive so the other had to be negative hope this helps;)))))
A.
if you have seen a newton's cradle this will make sense.
in order for both of them to travel at the same speed, the balls need to have the same mass and the speed to begin with tocontinue to travel at the same speed because mass can affect the impact of the force on the balls by each other, causing each ball to have different speeds.
Answer:

Explanation:
We are given that


d=1.9 cm=
Using 1m=100 cm
We have to find the electric field strength.

Using the formula





Mass of electron,m

Substitute the values


Answer:
Wavelength.
Explanation:
1 period, or wavelength, is measured from one crest to another or from one trough to another.
Here As we can see the figure that the end of the rope is pulled by some force F
Now as we can see that Piano is connected by a pulley which is passing over the pulley so effectively net force on the piano upwards will be 2F as it is connected by 2 ropes by the pulley
Now for constant velocity of the piano we will say

since velocity is constant so acceleration must be ZERO
so here we have

as we know here that
mg = 1000 N
so we will have


so here force must be 500 N