Carlota does 2000 J of work on a machine. The machine does 500 J of work. What is the efficiency of the machine?
A. 4%
B. 25%
C. 75%
D. 400%

Estimate the schwarzschild radius (in kilometers) for a mini-black hole formed when a superadvanced civilization decides to punish you (unfairly) by squeezing you until you become so small that you disappear inside your own event horizon. (assume that the your weight is 50 kg)

An element becomes a positively charged ion when itloses protons.loses electrons.gains electrons.gains neutrons.

Diego kicks a soccer ball from the end line. his fellow students time and mark the soccer ball as it moves down the field. the graph represents the ball's progress. based on the graph, during what time is the velocity constant and positive?