Rhea kicks a soccer ball at 13 km/h to sean. after kicking the ball, the speed of the soccer ball from rhea’s reference frame is 13 km/h. the speed of the soccer ball from sean’s reference frame is 22 km/h.
which conclusion is best supported by the information?
a. rhea is standing still after kicking the ball, and sean is running.
b. sean is standing still, and rhea is running while kicking the ball.
c. both soccer players are standing still after the ball is kicked.
d. both soccer players are running while the ball is in motion.

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.