What Happens to Velocities in a Head-On Collision?

  • Thread starter gcombina
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In summary: There are three of them- of energy, momentum, and angular momentum. All three of those laws are always obeyed after a collision, regardless of the type of collision. So, the vehicles will continue moving in the same direction and with the same speed.
  • #1
gcombina
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Homework Statement



Two objects of equal mass traveling toward each other with equal speeds undergo a head on collision. Which one of the following statements concerning their velocities after the collision is necessarily true?

(a) They will exchange velocities. (d) Their velocities will be zero.

(b) Their velocities will be reduced. (e) Their velocities may be zero.

(c) Their velocities will be unchanged.

Homework Equations



I know there is elastic and inelastic coallison
elastic keeps KE
inelastic loses KE
[/B]

The Attempt at a Solution



I would say that since both cars have SAME MASS AND SAME VELOCITIES they they will cancel each other right?
and therefore their velocities will be zero

so answer is D

but right answer is E, my question is why do they say "may be" zero?
 
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  • #2
gcombina said:
I know there is elastic and inelastic coallison
elastic keeps KE
inelastic loses KE
Have you been told what type of collision occurs?
 
  • #3
Bystander said:
Have you been told what type of collision occurs?
no, what you are reading is all they have given me
 
  • #4
So, you have no idea, and that is part of the problem statement. You are to consider the outcome of both possibilities, and select your answer to agree with both those outcomes.
 
  • #5
Bystander said:
So, you have no idea, and that is part of the problem statement. You are to consider the outcome of both possibilities, and select your answer to agree with both those outcomes.
right and my thought is that both velocities will cancel each other and be zero but its wrong, can u help me? my test is on Monday
 
  • #6
gcombina said:
since both cars have SAME MASS AND SAME VELOCITIES they they will cancel each other
What physical law are you basing that on? What, exactly, will cancel out?
 
  • #7
haruspex said:
What physical law are you basing that on? What, exactly, will cancel out?

because they are both at different directions, the force going to the right will cancel the force going to the left. The velocities will cancel, leaving the vehicles at zero speed
 
  • #8
gcombina said:
because they are both at different directions, the force going to the right will cancel the force going to the left. The velocities will cancel, leaving the vehicles at zero speed

oh shoot

should i use the third law of Newton? action/reaction?
 
  • #9
"BOTH." What is the outcome of an elastic collision? What is the outcome of an inelastic collision? Which answer is consistent with both outcomes?
 
  • #10
gcombina said:
because they are both at different directions, the force going to the right will cancel the force going to the left. The velocities will cancel, leaving the vehicles at zero speed
There is no law that says velocities cancel.
Forces can cancel, yes, but that doesn't tell you how the vehicles will move after collision.
Think "conservation laws".
 

FAQ: What Happens to Velocities in a Head-On Collision?

What is a collision and how does it happen?

A collision occurs when two or more objects come into contact with each other. This can happen in a variety of ways, such as two cars crashing into each other or a ball hitting a wall. The objects involved in the collision can experience changes in velocity and direction based on the force of impact.

What factors determine the severity of a collision?

The severity of a collision depends on several factors, including the relative speed and mass of the objects involved, the angle of impact, and the type of materials the objects are made of. Generally, the higher the speed and mass of the objects, the more severe the collision will be.

How can collisions be prevented or minimized?

Collisions can be prevented or minimized by following traffic laws and regulations, maintaining a safe distance from other vehicles, and avoiding distractions while driving. In industries such as construction and manufacturing, proper safety protocols and equipment can help prevent collisions in the workplace.

What are some common injuries that can result from collisions?

Injuries from collisions can range from minor cuts and bruises to more serious injuries such as broken bones, whiplash, and traumatic brain injuries. The type and severity of injuries will depend on the force and impact of the collision, as well as the use of safety equipment.

How do scientists study collisions?

Scientists study collisions by using mathematical models and conducting experiments in controlled environments. They also analyze data from real-life collisions to better understand the forces and factors involved. Technologies such as crash test dummies and high-speed cameras are often used to simulate and observe collisions in a safe and controlled manner.

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