THE INTERSTELLAR MEDIUM COMPOSED GAS AND DUST
I think they decrease echo and reduce noise, they do this by either absorbing vibrations or by scattering the sound so that echoes arrive at different times rather than reverberating as a standing wave. An echo is a reflection of a sound that arrives at the listener with a delay after the direct sound. The delay is usually proportional to the distance of the reflecting surface from the source and the listener.
Explanation:
90 kmhr—1 x 1000/3600 = 25ms—1
U = 0 ms—1
V = 25ms—1
t = 10 s
a = ?
a = V - U/t
a = 25 - 0/10
a = 25/10
a = 2.5 ms—1
Momentum of the object can be calculated by multiplying the mass of the object and the velocity of the moving object. In this case, the starting situation should be the object should be moving, else there is no velocity and thus momentum is equal to zero .Answer is C