A difference between mechanical and electromagnetic waves is a. Only mechanical waves can measure frequency

b. Only electromagnetic
waves travel through gas particles

c. Only electromagnetic waves travel
through space

d. Only mechanical waves include light

The astronauts on the space shuttle flights experienced an acceleration of 29 m/s2 (about 3 "g's") during lift-off. what upward force must the astronaut's seat apply to the astronaut in order to cause this acceleration? assume the astronaut's mass is 70 kg, and compute this force when the acceleration is near the earth's surface so their weight equals latex: mg m g .