Question
A 900kg car, traveling 13m/s to the right collides with a 3000kg semi truck initially at rest. After the 0.7s collision, the semi truck ends up moving 5.3m/s right. vert Jvert =15,900kgm/s before collision: P_(car)=11,700kgm/s P_(truck)=0 kgm/s after collision: P_(car)=square kgm/s P_(truck)=15,900kgm/s What direction did the car move after the collision? square v How fast did the car move after the collision? square m/s
Solution
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Ashby
Expert ยท Tutor for 3 years
Answer
To solve this problem, we will use the **law of conservation of momentum** and the given data. The total momentum before the collision must equal the total momentum after the collision.---### Step 1: Write down the known values- Mass of the car (
) =
- Initial velocity of the car (
) =
(to the right)- Mass of the truck (
) =
- Initial velocity of the truck (
) =
(at rest)- Final velocity of the truck (
) =
(to the right)The impulse on the truck is given as:
---### Step 2: Calculate the total momentum before the collisionThe total momentum before the collision is the sum of the momenta of the car and the truck:
---### Step 3: Calculate the total momentum after the collisionThe total momentum after the collision is the sum of the momenta of the car and the truck:
We know the momentum of the truck after the collision:
Using the law of conservation of momentum:
Solve for
:
---### Step 4: Determine the direction of the car's motion after the collisionThe negative sign in
indicates that the car is moving to the **left** after the collision.---### Step 5: Calculate the car's velocity after the collisionThe momentum of the car after the collision is related to its velocity by:
Substitute the known values:
Solve for
:
The negative sign confirms that the car is moving to the **left**, and its speed is:
---### Final Answers:1. **Direction of the car after the collision:** Left2. **Speed of the car after the collision:**