Question

A puck is moving on an air hockey table. Relative to an x, y coordinate system at time t = 0 s, the x components of the puck's initial velocity and acceleration are v0x = +3.5 m/s and ax = +5.8 m/s2. The y components of the puck's initial velocity and acceleration are v0y = +2.8 m/s and ay = -2.0 m/s2. Find (a) the magnitude v and (b) the direction è of the puck's velocity at a time of t = 0.50 s. Specify the direction relative to the +x axis.

Answer 1

at t = 0
Vx = 3.5 and Ax = 5.8
so at t = .5
Vx = 3.5 + 5.8*.5 = 6.4

Vy = 2.8 and Ay = -2
so at t = .5
Vy = 2.8 -2*.5 = 1.8

|v| = sqt(6.4^2 + 1.8^2)
= 6.65 m/s

tan theta = 1.8/6.4
so theta = 15.7 degrees north of east