Correct answer only !

as a roller coaster goes downhill

a) kinetic energy is converted into potential energy.

b) potential energy is converted into kinetic energy.

c) electrical energy is converted into potential energy.

d) potential energy is converted into electrical energy.

wind moving at higher speeds will transfer more energy to the water, resulting in stronger waves.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.