Answer:
True: For a sound wave to propagate, air particles must be displaced in the direction of propagation - it is the displacement of these particles that causes the eardrum to vibrate and recognize the sound.
The answer would be center of mass, B
Answer:
Option c. Inter-rater Reliability
Explanation:
Here, the rating is done by a group of data collectors under training for evaluation children's pain on Faces scale which is a scale ranging from 0 to 10 with different expressions or faces with a happy face at 0 to a crying face at 10.
Also in Inter-rater Reliability, the relative consistency of a study or test is assessed and the extent to which different group members rated the same behavior, the consistency of which is evaluated.
Thus it can also be helpful in interviews, etc.
Answer:
Option (b) is correct.
Explanation:
Elastic collision is defined as a collision where the kinetic energy of the system remains same. Both linear momentum and kinetic energy are conserved in case of an elastic collision.
Inelastic collision is defined as a collision where kinetic energy of the system is not conserved whereas the linear momentum is conserved. This loss of kinetic energy may due to the conversion to thermal energy or sound energy or may be due to the deformation of the materials colliding with each other.
As given in the problem, before the collision, total momentum of the system is 
and the kinetic energy is 
. After the collision, the total momentum of the system is , but the kinetic energy is reduced to 
. So some amount of kinetic energy is lost during the collision.
Therefor the situation describes an inelastic collision (and it could NOT be elastic).
