Search results
F net Δ t F net Δ t is known as impulse and this equation is known as the impulse-momentum theorem. From the equation, we see that the impulse equals the average net external force multiplied by the time this force acts. It is equal to the change in momentum.
- 18.5 Capacitors and Dielectrics
We can see from the equation for capacitance that the units...
- 10.2 Consequences of Special Relativity
Notice that when the velocity v is small compared to the...
- 8.3 Elastic and Inelastic Collisions
Elastic and Inelastic Collisions. When objects collide, they...
- 11.1 Temperature and Thermal Energy
8.1 Linear Momentum, Force, and Impulse; 8.2 Conservation of...
- 8.2 Conservation of Momentum
where p′ 1 and p′ 2 are the momenta of cars 1 and 2 after...
- 21.3 The Dual Nature of Light
Figure 21.10 shows a comet with two prominent tails. Comet...
- 22.1 The Structure of The Atom
Bohr was able to derive the formula for the hydrogen...
- 22.4 Nuclear Fission and Fusion
As shown in Figure 22.26, a neutron strike can cause the...
- 18.5 Capacitors and Dielectrics
Impulse: Change in Momentum. Change in momentum equals the average net external force multiplied by the time this force acts. \[\Delta p = F_{net} \Delta t\] The quantity \( F_{net}\Delta t\) is given the name impulse.
In equation form, F • t = m • Δ v. In a collision, objects experience an impulse; the impulse causes and is equal to the change in momentum. Consider a football halfback running down the football field and encountering a collision with a defensive back.
In classical mechanics, impulse (symbolized by J or Imp) is the change in momentum of an object. If the initial momentum of an object is p 1, and a subsequent momentum is p 2, the object has received an impulse J: =. Momentum is a vector quantity, so impulse is also a vector quantity.
Impulse-Momentum Theorem. The impulse-momentum theorem states that the change in momentum of an object equals the impulse applied to it. J = ∆p. If mass is constant, then… F∆t = m∆v. If mass is changing, then… F dt = m dv + v dm. The impulse-momentum theorem is logically equivalent to Newton's second law of motion (the force law). Units
To calculate the impulse using Equation 9.3.3, we need to know the force function F (t), which we often don’t. However, a result from calculus is useful here: Recall that the average value of a function over some interval is calculated by. f(x)ave = 1 Δx∫xfxif(x)dx. where Δ x = x f − x i.
Using the given data about the meteor, and making reasonable guesses about the shape of the meteor and impact time, we first calculate the impulse using Equation 9.6. We then use the relationship between force and impulse Equation 9.5 to estimate the average force during impact.
