You shine a laser beam through a grating with a known number of slits per millimeter and observe a pattern on a screen. Then you cover half of the grating with nontransparent material. What will you see

(a) There will be half as many bright fringes on the screen.(b) The bright fringes will be twice as close.(c) The bright fringes will be two times farther apart.(d) The location of the fringes will not change, but they will be a little bit wider and less bright.

d) The location of the fringes will not change, but they will be a little bit wider and less bright.

Explanation:

When one blocks half of the grating slits, the intensity of the interacting light is reduced, which reduces the brightness of the light. The angle of interference on the screen increases, thus is due to the reduced intensity of the light beams which makes the pattern become wider.

the velocity you are looking for is made up of two parts: horizontally velocity, vh, and its vertical velocity, vv. the actual velocity of the ball will be these two parts added together, and because velocity is a vector then they will need to be added vectorially.  

neglecting air resistance etc etc.,  

the horizontal velocity component will be constant (because there is no accelerating force in the horizontal direction.  

vh = 8 ms-1  

the vertical velocity component has an accelerating force: 'g'.  

using v = u +at where a = g = 9.81 ms-2.  

the vertical component of velocity, vv = 0 + gt = vv =9.81 x 2  

vv = 19.62 ms-1 . the zero appears because the virtical component of velocity at time t=0 is zero. remember, the ball was thrown horizontally.  

how fast it will be moving (it actual path (being a parabola )) will be the vector sum of these two.  

adding vectorally gives: -  

v = sqr root (8^2 + 19.62^2) = sqr root(64+384.9) = 21.18 or 21.2 ms-1

the answer is a. the yacht traveled from the dock north to the 200-meter marker in the bay in less than 5 minutes, giving the passengers several more hours to fish.

im doing peak rn so sry if its wrong