Bending occurs when one side of the wave enters the new medium before the other side of the wave. ... The bending occurs because the two sides of the wave are traveling at different speeds.
A spring scale measures weight because <span>It works by Hooke's Law, which states that the force needed to extend a </span>spring<span> is proportional to the distance that </span>spring<span> is extended from its rest position. Therefore, the </span>scale<span> markings on the </span>spring<span> balance are equally spaced. A </span>spring scale<span> can</span>not measure mass<span>, only </span>weight<span>. hope that helped</span>
Answer: 
Explanation:
Given
The velocities of the protons are 400 m/s and 450 m/s
Mass of the Proton is 
Since they travel in the opposite direction, therefore, their momentum cancels out each other.
Momentum is the product of mass and velocity

The direction of momentum is in the direction of proton having 450 m/s velocity.
The answer is c to take a pictures with the camera in the metal hall