According to the inverse square law of light, <span>apparent brightness will decrease by a factor of 9. Use the formula </span>

, to check it.
Best Answer: perpendicular to the direction of wave motion
think of you and a friend holding different ends of a rope. you shake your end side to side and the wave travels down to your friend's end. if you pay attention to a given segment of the rope, it moves, but it moves to the right and left while the wave travels forward. in a transverse wave, the constituents of the wave move perpendicular to the direction of motion of the wave itself.
a longitudinal wave, on the other hand, is the opposite. the constituents of the wave alternate moving in the same or opposite direction as the wave moves. this one is more like if you and your friend were holding onto a slinky. you give your end a push towards your friend, and you can see the wave move towards the other end.
hope that helps :D
I don't understand this question
I assume L=120 yards as the length of the football field.
1) The average speed is given by the total distance covered by the player divided by the time taken.
The total distance covered to go from one goal line to the other and then back to the 40-yards line is

And the time taken is t=22.4 s, so the average speed of the player is

2) The find the average velocity, we should also consider the direction (and the sign) of the velocity.
In the the first part of the motion, the player goes from one goal line to the other one, so he covers 120 y. However, in the second part of the motion he goes back by 80 y. Therefore, the net displacement of the player is

and so, the average velocity is