Which of these are not mechanical waves and can be used to send a signal to astronauts on the moon?
a) sound waves
b) radio waves
c) both sound waves and radio waves
d) neither sound waves or radio waves

If a textbook weighs 37.2 n on venus, and the book has a mass of 4.4 kg, what is the strength of gravity on venus? 8.9 m/s28.9 m/si don't have enough information,9.8 m/s2

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.

What is the average speed of a car that travels 40mph for 1 hour and 60 mph in another hour will mark brainliest