15) At the gym, a man pulls a bar on a machine that works the muscles of the upper back. It takes him 0.5 seconds to raise 30
kilograms of weights a vertical distance of 0.5 meters,
Which of these exerts the same power output? (Estimate g as 10 m/s2.)
A)
lifting 25 kilograms a distance of 2.4 meters in 2.0 seconds
B)
lifting 45 kilograms a distance of 2.4 meters in 3.0 seconds
o
leg pressing 45 kilograms a distance of 0.5 meters in 0,5 seconds
D)
bench pressing 30 kilograms a distance of 0.5 meter in 1.5 seconds

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.