What your saying doesn't make sense.
Answer is c that is he particles move perpendicular to the direction of the wave.
Answer:
342,000kg
Explanation:
p=mv
8.55*10^7 kg*m/s=m(900 km/h)
85,500,000 kg*m/s=m(900 km/h)
(85,500,000 kg*m/s)/(900 km/h)=m
Get same units.... 900km/h = 250m/s
m/s cancel in the division, you are left with just kg!!
85,500,000/250=342,000kg! That's it!
Refer to the diagram shown below.
The given data is
mass, kg Coordinates. m
------------- -----------------
2 (0, 0)
2 (2, 0)
4 (2, 1)
Total mass, M = 2+2+4 = 8kg
Let (x,y) be the coordinates of M.
Then, taking moments about the origin, we obtain
8x = 2*0 + 2*2 + 4*2 = 12
x = 1.5 m
8y = 2*0 + 2*0 + 4*1 = 4
y = 0.5 m
Answer: (1.5, 0.5) m