Question

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?

Answer 1

Answer:

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