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alterecho
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I'm trying to apply the equation from Wikipedia (http://en.wikipedia.org/wiki/Collision_response) to find the impulse of a collision. How do i find/calculate the surface normal n, which is a unit vector?
|r x n| = 20, agreed? This gives me j = (2*30)/(1/1+400/200) = 20.alterecho said:You're right. But when i apply the initial values as:
e = 1
[itex]V_{i}[/itex] = (10, -20)
[itex]W_{i}[/itex] = 0
r = (0, -20)
[itex]V_{p}[/itex] = (10, -20)
n = (-1, 1)
m = 1
I = 200
For Collision with a Wall/ground, I'm using equation from this site (modified version of the Wikipedia equation): http://www.myphysicslab.com/collision.html
j = [itex]\frac{−(1 + e) V_{p1} · n}{\frac{1}{m} + \frac{(r × n)^{2}}{I}}[/itex]
I get j = 59.4,
The impulse of a collision is calculated by multiplying the force of the collision by the time interval in which the force acts. This can be represented by the equation J = F x Δt, where J is the impulse, F is the force, and Δt is the time interval.
The unit of measurement for impulse is the Newton-second (N·s) in the SI system of units. This can also be expressed as kilogram-meter per second (kg·m/s) in the MKS system, or pound-second (lb·s) in the FPS system.
The direction of impulse is determined by the direction of the force acting on the object. The impulse vector points in the same direction as the force vector.
Yes, impulse can be negative. This occurs when the direction of the force and the direction of the object's motion are opposite. In this case, the impulse vector will point in the opposite direction of the force vector.
To calculate impulse in a collision, you will need to know the force of the collision and the time interval in which the force acts. This information can be obtained from measurements or calculations based on the masses and velocities of the objects involved in the collision.