what is the difference between the speed of longitudinal waves in air at 27 degree celcius and at -13 degree celcius . What is the speed at 0 degree celcius

Which simple machine is not part of this compound machine? a. lever b. pulley c. inclined plane d. wheel and axle

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

An element becomes a positively charged ion when itloses protons.loses electrons.gains electrons.gains neutrons.