A player strikes a hockey puck giving it a velocity of 30.252 m/s. The puck slides across the ice for 0.267 s after which time its velocity is 28.452 m/s. The acceleration of gravity is 9.8 m/s 2. If the mass of the puck is 179 g, what is the average drag force exerted on it by the ice?

The average drag force is 1.206 (-i) N

Explanation:

You have to apply the equations of Impulse:

I=FmedΔt

Where I and Fmed (the average force) are vectors.

The Impulse can also be expressed as the change in the quantity of motion (vector P)

I=P2-P1

P=mV (m is the mass and v is the velocity)

You can calculate the quantity of motion at the beggining and at the end of the given time:

Replace the mass in kg, dividing the mass by 1000 to convert it from g to kg.

P1 = (0.179kg) (30.252m/s) i = 5.414 i kg. m/s

P2=0.179kg) (28.452m/s) i = 5.092 i kg. m/s

Where i is the unit vector in the x-direction.

Therefore:

I = 5.092 i - 5.414 i = - 0.322 i

The average drag force is:

Fmed = I/Δt = - 0.322 i / 0.267s = - 1.206 i N