What element has 81 protons in the nuclei of atoms

All compounds are positively charged true or false

Water has a heat capacity of 4,184 J/kg*C. You have 2kg of water at a temperature of 98C. You want to raise the temperature to 100C. How much energy is needed to do this? 4,184J 16,736J 12,334J 9,445J

What is likely happening at the boundary between the Nazca plate and the Pacific plate?

An element's atomic number is 17. How many protons would an atom of this element have?

After landing on an unfamiliar planet, a space explorer constructs a simple pendulum of length 55.0 cm. The explorer finds that the pendulum completes 108 full swing cycles in a time of 132 s.

How do whales bats and dolphins use echolocation? A To scare away predators B To attract mates C To orient them selves and find food D To tell animals of there species where they are

How much force would be needed to move a car with the mass of 100kg to an acceleration of 5m/s/s?

A pendulum bob is made from a sphere filled with water. What would happen to the frequency of vibration of this pendulum if the sphere had a hole in it that allowed the water to leak out slowly?

Elias serves a volleyball at a velocity of 16 m/s. The mass of the volleyball is 0.27 kg. What is the height of the volleyball above the gym floor when its total mechanical energy is 41.70 J? Round to the nearest number.

Which of the following is the best description of a graph? A. Equations that can be plotted B. A representation of an equation C. Independent and dependent variables D. x and y lines