# I think this is another momentum question

• rottentreats64
In summary, the problem involves a hailstone with a mass of 0.012kg and a velocity of 20m/s creating a 0.20 cm dent in a car. The question asks for the average force exerted by the car to stop the hailstone. Potential formulas to use include momentum, kinematics, and the work-energy theorem. The trajectory and events of the hailstone's journey may need to be described in detail. The conversation also suggests using the equation v^2=-2a*s to find the acceleration and then the force, or using the work-energy theorem with the given information. However, the solution may be incorrect and there may be an issue with the time of impact calculation.

#### rottentreats64

i really have no clue what to do in this problem since there's a measurement for the dent...what formula am i supposed to use for this?4. During an autumn storm, a 0.012kg hail stone traveling at 20.0m/s made a 0.20 cm deep dent in the hood of Darnell’s new car. What average force did the car exert to stop the damaging hail stone?
so far i understand:
mass= .012kg
velocity= 20 m/s
and then there's the .20 cm deep dent but i dun knoe what's that need for?

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You could probably use momentum or kinematics, but the work-energy theorem is a better place to start

Can you describe, in detail, the trajectory that the hailstone has travelled, and everything that's happened to it?

Would it be right to use v^2=-2*a*s to find the acceleration and then force

If you do not know v^2=u^2+2as try to derive it using:

v=u+at

s=ut+at^2/2

ponjavic said:
Would it be right to use v^2=-2*a*s to find the acceleration and then force

If you do not know v^2=u^2+2as try to derive it using:

v=u+at

s=ut+at^2/2

But its a lot easier with energy. W=-KE0
Fd=KEo
F=KEo/d=mv^2/2d
Everything you need to plug in is given, using acceleration is reproving the work energy theorem with kinematics.

We had a similar problem in our physics class, but my physics teacher says the solution is incorrect.
1) How long was the impact, if it traveled .2 cm at 20 m/s? (This is the part that is incorrect.)
2) Ft=m(v_2-v_1)

## 1. What is momentum?

Momentum is a physics concept that describes the quantity of motion an object has. It is calculated by multiplying an object's mass by its velocity.

## 2. How is momentum different from velocity?

Velocity is a measure of an object's speed and direction, while momentum is a measure of an object's mass and velocity combined.

## 3. How is momentum conserved in a closed system?

In a closed system, the total momentum of all objects involved does not change. This means that if one object gains momentum, another must lose an equal amount of momentum.

## 4. How does momentum affect collisions?

Momentum plays a crucial role in collisions, as it determines the outcome of the collision. In an elastic collision, both momentum and kinetic energy are conserved, while in an inelastic collision, only momentum is conserved.

## 5. How is momentum related to force?

Force is defined as the rate of change of momentum. This means that the more momentum an object has, the more force is required to change its motion.