At a school in northern Norway a group of students is assigned a project to measure the speed of a puck during a hockey
Posted: Fri May 06, 2022 10:56 am
At a school in northern Norway a group of students is assigned a
project to measure the speed of a puck during a hockey hard shot
competition (suggestion: check a video on a ice hockey hard shot
competition to visualize the approximate situation). They test a
system made of a series of identical springs with elastic constant
k = 315 N/m which have one end fixed against the board of the rink
while the free end is made of a thick heavy foam block of mass Μ=
0.35 kg. The springs are placed side by side as to cover a large
section of the board and catch pucks shot over a broad angle. A
coach feeds a puck of mass m = 0.15 g to a shooter of mass M = 68
kg, by sliding the puck along the ice towards the shooter with a
speed v = 11.5 mi/h and an angle θ= 39 degrees with respect to the
direction between the shooter and the central spring.
The shooter swings the 1 meter-long hockey stick to hit the puck.
The swing can be divided into three parts: 1) on the way down the
shooter swings the stick through an angle α = 33 degrees with the
vertical direction in t = 0.25; 2) the stick makes contact with the
puck for a time t' = 0.26 second. During the swing the stick moves
in the direction of the central spring. Consider the stick swung as
a uniform rod that that rotates around one end and has a mass 1/8
of the mass of the shooter. Also consider that all the momentum is
transferred to the puck.
After being hit the puck slides across the ice and strikes the foam
at the end of one of the springs and remains embedded in it.
Find:
a) The average force exerted by the stick on the puck:
b) The expression x(t) for the oscillation for the spring after
the puck remains embedded in the foam at the end of the spring:
c) Briefly explain why basically only the central spring is
needed for the experiment and how the experiment can be used to
calculate the speed of shot:
project to measure the speed of a puck during a hockey hard shot
competition (suggestion: check a video on a ice hockey hard shot
competition to visualize the approximate situation). They test a
system made of a series of identical springs with elastic constant
k = 315 N/m which have one end fixed against the board of the rink
while the free end is made of a thick heavy foam block of mass Μ=
0.35 kg. The springs are placed side by side as to cover a large
section of the board and catch pucks shot over a broad angle. A
coach feeds a puck of mass m = 0.15 g to a shooter of mass M = 68
kg, by sliding the puck along the ice towards the shooter with a
speed v = 11.5 mi/h and an angle θ= 39 degrees with respect to the
direction between the shooter and the central spring.
The shooter swings the 1 meter-long hockey stick to hit the puck.
The swing can be divided into three parts: 1) on the way down the
shooter swings the stick through an angle α = 33 degrees with the
vertical direction in t = 0.25; 2) the stick makes contact with the
puck for a time t' = 0.26 second. During the swing the stick moves
in the direction of the central spring. Consider the stick swung as
a uniform rod that that rotates around one end and has a mass 1/8
of the mass of the shooter. Also consider that all the momentum is
transferred to the puck.
After being hit the puck slides across the ice and strikes the foam
at the end of one of the springs and remains embedded in it.
Find:
a) The average force exerted by the stick on the puck:
b) The expression x(t) for the oscillation for the spring after
the puck remains embedded in the foam at the end of the spring:
c) Briefly explain why basically only the central spring is
needed for the experiment and how the experiment can be used to
calculate the speed of shot: