a baseball flying through the air at 90 miles per hour
a baseball flying through the air at 45 miles per hour
a baseball flying through the air at 20 miles per hour
a baseball sitting on the ground
Which of the following is true about high-energy mechanical devices?
They usually need to be kept warm in order to preserve mechanical energy.
They usually need to be cooled to dissipate thermal energy build-up and prevent damage.
They usually convert radiant energy into electrical energy.
During an energy conversion, none of the energy is transferred as thermal energy because the devices are free of friction.
A 0. 100-kilogram apple hangs in a tree 1. 50 meters above the ground. Ignoring frictional effects, the total mechanical energy of the apple is _____.
0. 00 J
less than 1. 47 J but more than 0. 00 J
exactly 1. 47 J
more than 1. 47 J
A 0. 100-kilogram apple falls from a height of 1. 50 meters to 1. 00 meters. Ignoring frictional effects, what is the kinetic energy of the apple at this height?
0. 00 J
0. 49 J
0. 98 J
1. 47 J
A CD player uses 1,200 joules of energy in 60 seconds. What is the power rating of the CD player?
0. 05 W
A gust of wind pushes a beach ball with a force of 9 newtons. The ball rolls 10 meters in 3 seconds. What is the power of the wind?
Thank you so much!!!:D