What is the change in the total potential energy of the spring-mass-earth system (the horizontal rod is fixed, eventually, to the earth) as the mass moves the 21.0 cm upward from its release point? also, what is the speed of the mass after it has moved upwards by 21.0 cm from its release point?

What is found within a ranger tower overlooking a drained lake

¿qué parte de la patagonia está en peligro de exinción por su sobrepesca?

Ascientist is explaining how background cosmic radiation gives evidence of the big bang theory. she says that radiation has been detected everywhere equally as heat in the universe and is increasing. this has been shown to be residual radiation from the big bang. what error did the scientist make?