A hiker is at the bottom of a canyon facing the canyon wall closest to her. She shouts something and hears her echo 1.2 seconds later. If the sound wave travels at a speed of 340 m/s, how far away is the canyon wall in meters? (hint: to hear an echo the sound wave has to travel there and back)

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.