Question

In a lab experiment, two identical gliders on an air track are held together by a piece of string, compressing a spring between the gliders. While they are moving to the right at a common speed of 0.500 m/s, one student holds a match under the string and burns it, letting the spring force the gliders apart. One glider is then observed to be moving to the right at 1.300 m/s. (the string and spring both have negligible mass).

(a) What velocity does the other glider have?
(b) It the total kinetic energy of the two gliders after thecollision greater than, less than, or equal to the total kineticenergy before the collision? If greater, where did the extra energycome from? If less, where did the "lost" energy go?

Answer 1

a) - 0.300 m/s

b) The total kinetic energy will be greater after the collision because of the force from the spring that has separated them.

Step-by-step explanation:

Given:

Two identical glider

Common speed of gliders = 0.500 m/s

Speed of one glider after separation = 1.300 m/s

let the mass of each glider be 'm'

a) Now,

from the conservation of momentum, we have

Initial momentum = Final momentum

( m + m ) × 0.500 = m × 1.300 + m × v

here, v is the speed of the other glider after separation

thus,

2m × 0.500 = m × ( 1.300 + v )

or

1 = 1.300 + v

or

v = - 0.300 m/s

here the negative sign depicts the velocity is in opposite direction to the initial direction of motion

b) The total kinetic energy will be greater after the collision because of the force from the spring that has separated them.