Question

A hockey player hits a puck so that it comes to rest in 9 s after sliding 30 m on the ice. Determine (a) the acceleration in terms of ,​(4 marks) (b) the initial velocity and acceleration of the puck.​(5 marks)

Answer 1

Answer:

a) Acceleration, a = -u/9, where u is the initial velocity

b) Acceleration = 0.741 m/s², Initial velocity = 6.67 m/s

Explanation:

 We have equation of motion, v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.

a)  We have v = 0 m/s, t = 9 s

 So,    0 = u + a x 9

      Acceleration, a = -u/9, where u is the initial velocity

b) We have equation of motion , $s= ut+\frac{1}{2} at^2$, s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

 s = 30 m , u = -9a, t =9 s

 So,  $30= -9a*9+\frac{1}{2} *a*9^2\\ \\ 30=-40.5a\\ \\ a=-0.741m/s^2$

u = -9a = 6.67 m/s

So acceleration = 0.741 m/s², Initial velocity = 6.67 m/s