A small car meshes with a large truck in a head-on collision

[12boone]

Homework Statement

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average collision force is correct?
The truck experiences the greater average force.
>>> The small car experiences the greater average force.
The small car and the truck experience the same average force.
It is impossible to tell since the masses and velocities are not given.

Is this question right? I feel like a smaller object will have a greater force acting on it.

A 3.0-kg object moves to the right at 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left at 2.0 m/s. Which statement is correct?
The total momentum both before and after the collision is 24 kg∙ m/s.
The total momentum before the collision is 24 kg∙m/s, and after the collision is 0 kg∙m/s.
>>>The total momentum both before and after the collision is zero.
None of the above is true.

would the velocity of the 6.0kg mass be negative?

 

[alphysicist]

Hi 12boone,

Homework Statement

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average collision force is correct?
The truck experiences the greater average force.
>>> The small car experiences the greater average force.
The small car and the truck experience the same average force.
It is impossible to tell since the masses and velocities are not given.

Is this question right? I feel like a smaller object will have a greater force acting on it.

Think about Newton's laws for this question. One of the laws directly answers this question.

A 3.0-kg object moves to the right at 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left at 2.0 m/s. Which statement is correct?
The total momentum both before and after the collision is 24 kg∙ m/s.
The total momentum before the collision is 24 kg∙m/s, and after the collision is 0 kg∙m/s.
>>>The total momentum both before and after the collision is zero.
None of the above is true.

would the velocity of the 6.0kg mass be negative?

Whether you call the left direction positive or negative is up to you; the important thing is that the velocity of the 6kg object will have the opposite sign as the velocity of the 4kg object, since they are in opposite directions.

 

[baba89]

I cannot determine if the question is right or wrong, as it is not within my field of expertise. However, I can provide an explanation based on the principles of physics.

In a head-on collision, the force experienced by each object depends on its mass and velocity. The larger the mass and the higher the velocity, the greater the force experienced. Therefore, in this scenario, the small car, with a lower mass, will experience a greater average force compared to the large truck.

As for the second question, the total momentum before and after the collision will always be equal, according to the law of conservation of momentum. In this case, the total momentum before the collision is 24 kg∙m/s, with the 3.0-kg object moving at 4.0 m/s and the 6.0-kg object moving at -2.0 m/s (since it is moving in the opposite direction). After the collision, the total momentum will be zero, as the objects will come to a stop. Therefore, the correct statement is that the total momentum both before and after the collision is zero.

In conclusion, the smaller object will experience a greater average force in a head-on collision, and the total momentum before and after the collision will always be equal.