What is the Impulse and Average Force in a Collision between a Ball and Wall?

In summary, a 300g ball strikes a wall at an angle of 30 degrees with a speed of 6.0m/s and rebounds with the same speed and angle after being in contact with the wall for 10ms. The impulse on the ball from the wall is 6 kg*m/s in the j direction and the average force on the wall from the ball is 180 N.
  • #1
Ready2GoXtr
75
0

Homework Statement


A 300g ball with a speed v of 6.0m/s strikes a wall at an angle theta of 30 degrees and then rebounds with the same speed and angle. It is in contact with the wall for 10ms. In unit-vector notation, what are (a) the impulse on the ball from the wall and (b) the average force on the wall from the ball?

http://ready2goxtr.googlepages.com/problem936.jpg


Homework Equations


Pi = Pf

Delta (P) = I
P = mv
<v being a vector>

Favg = I / (delta T)


The Attempt at a Solution



m = .3kg v = 6m/s theta = 30 degrees t = 10ms = .01s

a) Pi = PF

Pi = .3kg(Vcos(-30) i + Vsin(-30) j) = .26 kg * m/s i - 3 kg * m/s j

Pf = .3kg(Vcos(30) i + Vsin(30) j) = .26 kg * m/s i + 3 kg * m/s j

I = Delta (P) I = PF - PI

PF - PI = 6 kg * m/s j


b) I = sqrt(a^2 + b^2)
6kg * m/s / .01s = 600 N



I know i did it wrong. And thank you ahead of time.
 
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  • #2
Ready2GoXtr said:
Pi = .3kg(Vcos(-30) i + Vsin(-30) j) = .26 kg * m/s i - 3 kg * m/s j

Pf = .3kg(Vcos(30) i + Vsin(30) j) = .26 kg * m/s i + 3 kg * m/s j
Double check your arithmetic.
 
  • #3
whats wrong with it? Sorry if I am a bit slow, all the chemotherapy i had last year sort of slowed me down i think.
 
  • #4
Ready2GoXtr said:
whats wrong with it?
For example: .3*6*sin(30) = ?
 
  • #5
Oh Duh me. 0.9 but still, I highly doubt that I = 1.8 kg * m/s J
 
  • #6
well in that case I = 1.9 kg * m/s J and Favg = 180 N
 
  • #7
Okay so that must be right answer then?
 
  • #8
Sounds good to me. Express your answers using unit vectors.
 
  • #9
Do i need to open up a new post for a new question?
 
  • #10
Ready2GoXtr said:
Do i need to open up a new post for a new question?
In general: If it's a new problem, use a new thread. If it's a followup question on the same problem, ask it here.
 

1. What is a collision?

A collision is a physical interaction between two or more objects where they come into contact and exert forces on each other. This can result in a change in motion or deformation of the objects involved.

2. What is impulse?

Impulse is the change in momentum of an object that occurs when it experiences a force over a period of time. It is equal to the force applied multiplied by the time it is applied for.

3. How is impulse related to collision?

In a collision, the impulse is equal to the change in momentum of the objects involved. This can be calculated using the formula J = Δp = mΔv, where J is impulse, Δp is the change in momentum, m is the mass of the object, and Δv is the change in velocity.

4. What factors affect the impulse in a collision?

The magnitude and direction of the force applied, as well as the duration of the collision, can affect the impulse in a collision. The mass and velocity of the objects also play a role in determining the impulse.

5. Why is understanding collision and impulse important?

Understanding collision and impulse is important in many fields of science and engineering, such as in the design of safety features in vehicles, analysis of sports injuries, and study of celestial impacts. It also helps us understand and predict the behavior of particles and objects in motion.

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