Pb(no3)2 + 2ki → pbi2 + 2kno3 is what kind of reaction?

It is really hard for me right know

The particle p starts from rest at point a at time t = 0 and changes its speed thereafter at a constant rate of 2.8g as it follows the horizontal path shown. determine the magnitude and direction of its total acceleration (a) just before point b, (b) just after point b, and (c) as it passes point c. state your directions relative to the x-axis shown (ccw positive) and choose the angle with the smallest magnitude.

The velocity of sound wave in air at 35°c is 353m/s, calculate the velocity of sound at 46°c