Question
A hockey puck with a mass of 0.18 kg travels at a velocity of 40 m/s toward a goalkeeper. The goalkeeper has a mass of 120 kg and is at rest. Assuming a closed system, find the total momentum of the puck before the puck is caught by the goalkeeper. (1 point) Responses 0 kg.m/s 0 kg.m/s 7.2 kg.m/s 7.2 kg.m/s -5.3 kg.m/s -5.3 kg.m/s 6.4 kg.m/s 6.4 kg.m/s Question 2 A hockey puck with a mass of 0.18 kg travels at a velocity of 40 m/s toward a goalkeeper. The goalkeeper has a mass of 120 kg and is at rest. Assuming a closed system, find the total momentum of the goalkeeper and puck after the puck is caught by the goalkeeper.(1 point) Responses 6.4 kg.m/s 6.4 kg.m/s 7.2 kg.m/s 7.2 kg.m/s 4,807 kg.m/s 4,807 kg.m/s 5.3 kg.m/s 5.3 kg.m/s Question 3 What object has the greater momentum after the puck is caught? (1 point) Responses The goalkeeper The goalkeeper The hockey puck The hockey puck The net. The net. The ice The ice Question 4 What is your justification for choosing the item you did as having the greater momentum?(1 point) Responses Momentum is absorbed by the net as the puck gets close to it. Momentum is absorbed by the net as the puck gets close to it. Momentum is mass times velocity so the momentum would stay inside the hockey puck after it is caught. Momentum is mass times velocity so the momentum would stay inside the hockey puck after it is caught. Momentum is absorbed by the ice and is not transferred after it is completely absorbed. Momentum is absorbed by the ice and is not transferred after it is completely absorbed. Momentum is mass times velocity so the greater mass would contain more of the momentum. Momentum is mass times velocity so the greater mass would contain more of the momentum. Skip to navigation
Answers
GPT-4o mini
Let's tackle each question step by step, starting with the calculations for momentum.
### Question 1: Total Momentum of the Puck Before Caught
The momentum \( p \) of an object is calculated using the formula:
\[
p = m \cdot v
\]
where \( m \) is the mass and \( v \) is the velocity.
For the hockey puck:
- Mass \( m = 0.18 \) kg
- Velocity \( v = 40 \) m/s
Calculating the momentum of the puck:
\[
p_{\text{puck}} = 0.18\, \text{kg} \times 40\, \text{m/s} = 7.2\, \text{kg.m/s}
\]
The goalkeeper is at rest, so his initial momentum is 0. Therefore, the total momentum before the puck is caught is simply:
\[
\text{Total momentum} = p_{\text{puck}} + p_{\text{goalkeeper}} = 7.2\, \text{kg.m/s} + 0 = 7.2\, \text{kg.m/s}
\]
**Response for Question 1: 7.2 kg.m/s**
---
### Question 2: Total Momentum After the Puck is Caught
When the puck is caught by the goalkeeper, we consider the system of the puck and the goalkeeper as a single object.
The combined mass after the puck is caught is:
\[
m_{\text{combined}} = m_{\text{puck}} + m_{\text{goalkeeper}} = 0.18\, \text{kg} + 120\, \text{kg} = 120.18\, \text{kg}
\]
Since momentum is conserved in a closed system, the total momentum after catching the puck is equal to the total momentum before catching the puck (as previously calculated):
\[
\text{Total momentum after} = 7.2\, \text{kg.m/s}
\]
**Response for Question 2: 7.2 kg.m/s**
---
### Question 3: Greater Momentum After the Puck is Caught
After the puck is caught, the momentum of the combined system (goalkeeper + puck) is \( 7.2\, \text{kg.m/s} \).
The hockey puck, once caught, is now part of the goalkeeper's mass and does not maintain separate momentum. Thus, the only object in consideration for momentum in the end result is the combined mass of the puck and the goalkeeper.
**Response for Question 3: The goalkeeper**
---
### Question 4: Justification for Greater Momentum
The correct reasoning here is based on the fact that momentum is not lost but transferred. The momentum that was initially in the puck is now in the combined system of the goalkeeper and the puck.
The correct justification should note that the goalkeeper's mass contributes to the overall momentum of the system, effectively illustrating that the momentum remains within the state of the puck and goalkeeper since they now move together.
**Response for Question 4: Momentum is mass times velocity so the greater mass would contain more of the momentum.**
### Question 1: Total Momentum of the Puck Before Caught
The momentum \( p \) of an object is calculated using the formula:
\[
p = m \cdot v
\]
where \( m \) is the mass and \( v \) is the velocity.
For the hockey puck:
- Mass \( m = 0.18 \) kg
- Velocity \( v = 40 \) m/s
Calculating the momentum of the puck:
\[
p_{\text{puck}} = 0.18\, \text{kg} \times 40\, \text{m/s} = 7.2\, \text{kg.m/s}
\]
The goalkeeper is at rest, so his initial momentum is 0. Therefore, the total momentum before the puck is caught is simply:
\[
\text{Total momentum} = p_{\text{puck}} + p_{\text{goalkeeper}} = 7.2\, \text{kg.m/s} + 0 = 7.2\, \text{kg.m/s}
\]
**Response for Question 1: 7.2 kg.m/s**
---
### Question 2: Total Momentum After the Puck is Caught
When the puck is caught by the goalkeeper, we consider the system of the puck and the goalkeeper as a single object.
The combined mass after the puck is caught is:
\[
m_{\text{combined}} = m_{\text{puck}} + m_{\text{goalkeeper}} = 0.18\, \text{kg} + 120\, \text{kg} = 120.18\, \text{kg}
\]
Since momentum is conserved in a closed system, the total momentum after catching the puck is equal to the total momentum before catching the puck (as previously calculated):
\[
\text{Total momentum after} = 7.2\, \text{kg.m/s}
\]
**Response for Question 2: 7.2 kg.m/s**
---
### Question 3: Greater Momentum After the Puck is Caught
After the puck is caught, the momentum of the combined system (goalkeeper + puck) is \( 7.2\, \text{kg.m/s} \).
The hockey puck, once caught, is now part of the goalkeeper's mass and does not maintain separate momentum. Thus, the only object in consideration for momentum in the end result is the combined mass of the puck and the goalkeeper.
**Response for Question 3: The goalkeeper**
---
### Question 4: Justification for Greater Momentum
The correct reasoning here is based on the fact that momentum is not lost but transferred. The momentum that was initially in the puck is now in the combined system of the goalkeeper and the puck.
The correct justification should note that the goalkeeper's mass contributes to the overall momentum of the system, effectively illustrating that the momentum remains within the state of the puck and goalkeeper since they now move together.
**Response for Question 4: Momentum is mass times velocity so the greater mass would contain more of the momentum.**