Questions and Answers
The linear impulse and momentum equation is obtained by integrating the ______ with respect to time.
equation of motion
Which parameter is not involved in the linear impulse and momentum equation? (Select one option)
Calculate the impulse due to the force. (Select one option)
Determine the force F if the particle's mass is 2 kg. (Select one option)
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Determine the net impulse on the aircraft over t = 10 s. (Select one option)
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Determine the net impulse on the cabinet during this time interval. (Select one option)
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The internal impulses acting on a system of particles always __________.
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Weight is a/an __________ during impulse-momentum analysis.
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Over the short time span of a tennis ball hitting the racket, the ball's weight can be considered _____________.
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How many impulsive forces act on the drill rod during drilling? (Select one option)
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What is the velocity of the block immediately after impact? (Select one option)
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During the impact with the bat, how many impulses of importance are used to find the final velocity of the ball? (Select one option)
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When the motion of one or both particles is at an angle to the line of impact, the impact is said to be ________.
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The ratio of the restitution impulse to the deformation impulse is called ________.
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Can one of the balls leave the impact with a kinetic energy greater than before the impact? (Select one option)
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Under what condition is the energy lost during a collision maximum? (Select one option)
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If the velocity of block A after the collision is 4 m/s, what is (vB)2? (Select one option)
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If e = 0.8, (vx) 2 is _____ after the collision. (Select one option)
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Select the correct expression for the angular momentum of a particle about a point.
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The sum of the moments of all external forces acting on a particle is equal to what? (Select one option)
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If a particle moves in the x - y plane, its angular momentum vector is in the? (Select one option)
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If there are no external impulses acting on a particle, what can be said about momentum conservation? (Select one option)
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Which of the following principles can be applied to solve for the velocity of the ball when r = 2 ft? (Select one option)
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If a particle moves in the z - y plane, its angular momentum vector is in the? (Select one option)
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Study Notes
Equation of Motion
- Linear impulse and momentum equation is derived by integrating the friction force over time.
- Displacement is not a parameter in the linear impulse and momentum equation, while velocity, time, and force are involved.
Impulse Calculations
- Impulse due to a force can be calculated using the area under the force-time curve. For example, a force of 10 N applied for 1 second yields an impulse of 10 kg·m/s.
- If a constant vertical force of 981 kN is exerted on an aircraft hovering for 10 seconds, the net impulse is 0 kN·s, as the initial and final velocities are the same.
Forces and Impulses
- Internal impulses acting on a particle system always sum to zero.
- Weight can generally be considered a non-impulsive force during short interactions due to its negligible effect on momentum change.
- The impact force on a drill rod during drilling involves two impulsive forces, neglecting the rod's weight.
Collision Dynamics
- When a bullet embeds into a block, the block's velocity can be calculated using conservation of momentum principles; for example, a 20 g bullet at 1200 m/s results in a block velocity of 75 m/s post-impact.
- During a baseball bat impact, one significant impulse determines the final velocity of the ball.
Coefficient of Restitution
- The restitution coefficient relates the restitution impulse to the deformation impulse in a collision.
- A coefficient of restitution of 0.79 implies that one ball may leave a collision with greater kinetic energy than before.
- Maximum energy loss in a collision occurs when the coefficient of restitution (e) is 0.0, indicating a perfectly inelastic collision.
Angular Momentum
- Angular momentum of a particle about a point is calculated as ( r \times (m v) ).
- If external impulses are absent, both linear momentum and angular momentum are conserved.
- The vector direction of angular momentum for particles in the x-y plane is along the z direction.
Motion Transformation
- The time rate of change of angular momentum is equivalent to the sum of the moments of all external forces acting on a particle.
- If a particle moves in the z-y plane, its angular momentum vector is aligned with the x direction.
Miscellaneous Principles
- In a scenario where a ball moves in a circular path while a cord is pulled down, principles of energy, linear momentum, or mass conservation do not apply in calculating the ball's new velocity.
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Description
Test your understanding of key concepts from Dynamics Chapter 15 with these flashcards. This quiz focuses on important terms and definitions related to impulse and momentum. Challenge yourself and reinforce your knowledge of the equations of motion and displacement.
