Which element, represented by x, reacts with fluorine to produce the compound xf2? (1) aluminum (3) calcium (2) argon (4) sodium

Where on earth would physical weathering from temperature changes are least common?

Which force is greater the earth's pull on the moon or the moon's pull on the earth

What happens when a plastic lid sprinkled with iron filings is placed over a magnet?

Identify one harmful environmental change that occurs when a volcano erupts.

Describe the relationship of attractive forces between molecules

A cricketer can throw a ball to a maximum horizontal distance of 100m. How much high above the ground can he throw same ball

What is the relationship between the slope of the position graph of an object and its velocity?

Differeniate between thermal energy and heat

The term that describes the time when the sun's are directly over the equator is:

A submarine can detect an approaching enemy submarine using sonar. If a stationary submerged submarine emits a 100kHz tone and receives a tone Doppler shifted by 200Hz, calculate the speed of the enemy submarine if the speed of sound in salt water