A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of
-2.0 m/s. What is the velocity of the red ball after the collision?
A. zero.
B. -2.0 m/s.
C. +3.0 m/s.
D. +2.5 m/s.
E. +5.0 m/s.
I think zero but need a second opinion PLZ!! =)
Yes, the answer is A. zero.
To determine the velocity of the red ball after the collision, we can apply the principle of conservation of momentum. According to this principle, the total momentum before the collision should be equal to the total momentum after the collision.
The momentum (p) of an object is given by the product of its mass (m) and velocity (v). Since the red and yellow balls have equal mass, we can simplify our calculation by using a common mass value.
Before the collision, the red ball has a mass (m) and a velocity (v) of +3.0 m/s. The momentum of the red ball before the collision is then:
p(red before) = m * v = m * 3.0 m/s
The yellow ball has the same mass (m) and a velocity (v) of -2.0 m/s. The momentum of the yellow ball before the collision is:
p(yellow before) = m * v = m * -2.0 m/s
The total momentum before the collision is the sum of the individual momenta:
p(total before) = p(red before) + p(yellow before)
After the collision, the red ball's velocity changes. Let's assume its velocity after the collision is (v').
The momentum of the red ball after the collision is:
p(red after) = m * v'
Since there is no external force acting on the system, the total momentum after the collision should be equal to the total momentum before the collision:
p(total before) = p(total after)
This can be expressed as:
p(red before) + p(yellow before) = p(red after)
Substituting the momenta:
m * 3.0 m/s + m * -2.0 m/s = m * v'
Simplifying the equation:
3.0 - 2.0 = v'
Therefore, the velocity of the red ball after the collision is +1.0 m/s.
So, the correct answer is not listed among the options provided.
To solve this problem, we can use the principle of conservation of momentum, which states that the total momentum before a collision is equal to the total momentum after the collision, assuming no external forces are acting on the system.
The momentum of an object is equal to the product of its mass and velocity. In this case, the red ball and the yellow ball have equal masses.
Before the collision, the momentum of the red ball is given by:
Momentum_red = mass_red * velocity_red = mass_yellow * velocity_yellow
Substituting the given values into the equation, we have:
mass_red * velocity_red = mass_yellow * velocity_yellow
(velocity_red) = (mass_yellow * velocity_yellow) / mass_red
Now let's calculate the values:
velocity_red = (2) * (-2.0 m/s) / 2 = -2.0 m/s
Therefore, the velocity of the red ball after the collision is -2.0 m/s.
The correct answer is B. -2.0 m/s.