A machine used 20 J of energy to make a bicycle start. However, 6 J of energy was
wasted as heat. What is the percentage
efficiency of the machine?
a 30%
b 75%
C 70%
d 60%​

Pls pls pls pls ! describe, in your own words, how you found the epicenter of the earthquake.

What is a carrier wave and how does it affect what you hear on the radio

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?