54 Questions
What is the equation for conservation of kinetic energy in an elastic collision?
$K_i = K_f + \ rac{1},{2}m_1v_{1i}^2 + \ rac{1},{2}m_2v_{2i}^2$
How many unknown quantities can be solved if no more than two of the seven quantities in Equations 9.25 and 9.26 are unknown?
Four
If the collision is inelastic, is kinetic energy conserved?
No
What is the equation for momentum conservation in the x direction?
$p_{ix} = p_{fx}$
What is the equation for momentum conservation in the y direction?
$p_{iy} = p_{fy}$
In an elastic collision, what is the relationship between the total kinetic energy before and after the collision?
They are equal
What does Equation 9.27 represent?
Conservation of kinetic energy in an elastic collision
What is the equation for the x component of momentum?
$p_x = mv_x$
What is the equation for the y component of momentum?
$p_y = mv_y$
What should you do once you have determined your result?
Check if the answers are consistent with the mental and pictorial representations and if they are realistic
What is conserved in a collision of two particles?
momentum
In what directions is momentum conserved in a collision of two particles?
x, y, and z
What are the component equations for conservation of momentum in a two-dimensional collision?
$m_1v_{1ix} + m_2v_{2ix} = m_1v_{1fx} + m_2v_{2fx}$ and $m_1v_{1iy} + m_2v_{2iy} = m_1v_{1fy} + m_2v_{2fy}$
What is a glancing collision?
An event where particle 1 and particle 2 collide and move at angles with respect to the horizontal
What is the equation for conservation of momentum in the x direction in a glancing collision?
$\Delta p_x = 0 \implies p_{ix} = p_{fx} \implies m_1v_{1i} = m_1v_{1f}\cos(u) + m_2v_{2f}\cos(f)$
What is the equation for conservation of momentum in the y direction in a glancing collision?
$\Delta p_y = 0 \implies p_{iy} = p_{fy} \implies 0 = m_1v_{1f}\sin(u) - m_2v_{2f}\sin(f)$
Why does the equation for conservation of momentum in the y direction have a minus sign?
After the collision, particle 2 has a downward y component of velocity
What are the symbols v in the equations for conservation of momentum?
Speeds, not velocity components
True or false: The direction of the component vector is indicated explicitly with plus or minus signs.
True
True or false: If the collision is elastic, we can use Equation 9.17 (conservation of kinetic energy) with $v_{2i}=0$.
True
True or false: In an elastic collision, kinetic energy is conserved.
True
True or false: In an inelastic collision, kinetic energy is conserved.
False
True or false: If the collision is perfectly inelastic, the final velocities of the two objects are equal.
True
True or false: In a glancing collision, momentum is conserved in the x direction.
False
True or false: In a glancing collision, momentum is conserved in the y direction.
True
True or false: If the collision is inelastic, additional information is probably required.
True
True or false: The equation for conservation of momentum in the x direction in a glancing collision is $p_{ix} = p_{fx}$.
False
True or false: The equation for conservation of momentum in the y direction in a glancing collision is $p_{iy} = p_{fy}$.
True
True or false: Momentum is conserved in each of the x, y, and z directions in a collision of two particles.
True
True or false: The game of billiards involves multiple collisions of objects moving on a two-dimensional surface.
True
True or false: In a two-dimensional collision, there are two component equations for conservation of momentum.
True
True or false: In a glancing collision, particle 1 moves at an angle u with respect to the horizontal and particle 2 moves at an angle f with respect to the horizontal.
True
True or false: The law of conservation of momentum can be applied in component form for a glancing collision.
True
True or false: The initial y component of momentum of a two-particle system is always zero in a glancing collision.
True
True or false: The equation Dp x = 0 represents the conservation of momentum in the x direction for a glancing collision.
True
True or false: The equation Dp y = 0 represents the conservation of momentum in the y direction for a glancing collision.
True
True or false: The equation Dp y = 0 includes a minus sign because after the collision, particle 2 has a downward y component of velocity.
True
True or false: In a glancing collision, the total kinetic energy before and after the collision is conserved.
False
Which equation can be used to determine the motion after an elastic collision?
Equation 9.27
Which of the following is true about solving a problem involving collisions between two particles in two dimensions?
The system of particles must be isolated
What is the equation for conservation of momentum in the x direction in a glancing collision?
$p_{ix} = p_{fx}$
How many unknown quantities can be solved if no more than two of the seven quantities in Equations 9.25 and 9.26 are unknown?
Three
What is the equation for conservation of kinetic energy in an elastic collision?
$K_i = K_f$
True or false: If the collision is inelastic, kinetic energy is conserved.
False
What are the component equations for conservation of momentum in a two-dimensional collision?
$p_{ix} = p_{fx}$ and $p_{iy} = p_{fy}$
True or false: The equation $Dp_y = 0$ includes a minus sign because after the collision, particle 2 has a downward y component of velocity.
True
True or false: In a glancing collision, momentum is conserved in the x direction.
True
What should you do once you have determined your result?
Check to see if your answers are consistent with the mental and pictorial representations
Which equations represent the conservation of momentum in the x and y directions for a two-dimensional collision?
$m_1v_{1ix} + m_2v_{2ix} = m_1v_{1fx} + m_2v_{2fx}$ and $m_1v_{1iy} + m_2v_{2iy} = m_1v_{1fy} + m_2v_{2fy}$
What is the equation for the x component of momentum in a glancing collision?
$m_1v_{1ix} + m_2v_{2ix} = m_1v_{1fx} + m_2v_{2fx}$
What is the equation for the y component of momentum in a glancing collision?
$m_1v_{1iy} + m_2v_{2iy} = m_1v_{1fy} + m_2v_{2fy}$
What is the equation for conservation of kinetic energy in an elastic collision?
$m_1v_{1i}^2 + m_2v_{2i}^2 = m_1v_{1f}^2 + m_2v_{2f}^2$
What is a glancing collision?
A collision in which the objects move at an angle with respect to the horizontal after the collision.
What is conserved in a collision of two particles?
Momentum
Test your knowledge of collisions in two dimensions with this quiz. Learn about the conservation of momentum in different directions and explore the fascinating world of billiards.
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