What is the meaning of the gravity?

What is the role of the mid ocean ridge in the movement of lithosphere?

A geologist estimates that a large boulder weighs 7840 N. What should he estimate the mass of this boulder to be? A. 650 kg B. 740 kg C. 780 kg D. 800 kg

The velocity of any wave can be calculated from its frequency and wavelength. How fast (in meters per second) is a wave moving if its six waves go by in a second and its wavelength is two meters? A. 1/3 B. 3 C. 8 D. 12

What force prevents a machine from having 100% efficiency

Which of these events is most likely to occur due to the interaction between Earth's magnetic field and charged particles blowing away from the sun? a. gravity in space decreases b. auroras are visible at the poles c.

Select all the correct answers. Copper is listed in the 29th position in the periodic table. It's used for conducting electricity. What is copper? a metal a metalloid a nonmetal a noble gas an element

Neutron stars are smaller in size than less massive white dwarfs. a. True b. False

A lightning bolt carrying 30,000 A lasts for 50 micro-seconds. If the lightning strikes an airplane flying at 20,000 feet, what is the charge deposited on the plane?

David walks 3 km north, and then turns east and walks 4 km

In a Millikan oil-drop experiment, the charges on several different oil drops were as follows: - 5.92; - 4.44; - 2.96; - 8.88. The units are arbitrary.