A marathon runner is running across a bridge. She has 10,000 J of kinetic energy, and she has 20,000) of potential energy because she is on the bridge (above the ground). What is her mechanical energy?
30,000
10.000
20,000
15,000

an obstruction

answer: good job it's all correct !

explanation:

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2