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

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

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

Step-by-step 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+(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+(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