In a real machine, not all of the input work is available as output work. Explain why.

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?

*30 points + brainliest answer* gravity is pulling an object into the sun. the closer the object gets to the sun, the greater the gravitational force that acts on the object, increasing its acceleration. a line graph plotting the speed of the object against time would have which shape? a: straight line of positive slope b: curved line that slopes upward c: curved line that slopes downward d: straight line of negative slope