A hockey puck is given an initial speed of 5.30 m/s. If the coefficient of friction between the puck and ice is 0.052, how far does the puck slide before coming to rest

Respuesta :

Let m be the mass of the puck. Then the upward normal force exerted by the ice has magnitude n = mg (since Newton's law says the net force on the puck in the vertical direction is ∑ F = n - mg = 0).

Then the frictional force applies a force of magnitude f = 0.052mg, and Newton's second law says the net horizontal force acting on the puck is

∑ F = -f = ma

Solve for the acceleration a :

-0.052mg = ma

a = -0.052 (9.8 m/s²)

a ≈ -0.510 m/s²

Assuming constant friction, the puck slides to a rest over a distance x such that

0² - (5.30 m/s)² = 2ax

Solve for x :

x = -(5.30 m/s)²/(2a)

x = -(5.30 m/s)² / (2 (-0.510 m/s²))

x ≈ 27.6 m