PLS HELP !! Which of these must be true for a perfectly elastic collision?

Select one:

A: Kinetic energy is conserved
B: The velocity of the first object will not transfer to the second object
C: The objects will stick together
D: The masses must be equal​

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) sketch the trajectory using an appropriate coordination system. b) how long for the projectile to reach the ground. c) how far did projectile travel horizontally before striking the ground. d) determine the projectilex & y position at t-1.3s e) determine the magnitude and direction of projectile velocity at t= 1.3s f) determine the magnitude and direction of projectile acceleration at t-1.3s

What is the gravitational attraction between a dating couple whose centers of mass are 0.630 m apart if the boy weighs 715 n and the girl weighs 465 n?

Employer informs its employees that it will hold a substantial cash prize drawing for each work group at the end of each month in which no employee in the work group sustains a lost-time injury. tyra reports an injury that she sustained while operating a mechanical power press. tyra did not violate any employer safety rules when she sustained her injury. tyra’s injury requires her to miss work for two days. her employer cancels the cash prize drawing for that month for tyra’s work group because of tyra’s lost-time injury. did the employer misuse an incentive program to retaliate against tyra?