What can you use to test substancea for their ph value if you dont have a strip of litmus paper handy?

Acar accelerates from 5.0 m/s to to 11 m/s at a rate of 3.0 m/s^2. how far does it travel while accelerating? 20m 117m 43m 16m

Wavelength,frequency,and energy are related.what happens to a wave as it’s wavelength gets shorter?

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?