Explain why an electromagnet usually has a core of iron or steel

Una campana de 1000 kg está en un campanario a 20m del suelo. Calcula la energía.

A solenoid with a ferromagnetic core is called a circuit. a. True b. False

Which best describes work? Select one of the options below as your answer: a. holding a pencil b. lifting a feather c. dropping a ball

Which of these types of organisms is there more of on Earth? A. goat B. human C. dandelion D. bacterium

Particles of charge + 75, + 48, and - 85μC are placed in a line. The center one is 0.35 m from each of the others. Calculate the net force on each charge due to the other two.

Which statement best describes the movement of particles when a wave travels through a medium? The particles are

What is the acceleration of all objects due to gravity? What does this mean?

Which is the correct formula for cellular respiration? a. 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2 b. CO2 + H2O → C6H12O6 + O2 c. C6H12O6 + O2 → CO2 + H2O d. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy

A tree is standing in the middle of a meadow. As you watch, the wind begins to blow and the tree bends. Which statement best explains how you could tell that a net force was acting on the tree? OA) The tree had momentum.

Consider two cars, a 700kg Porsche and a 600kg Honda Civic. The Porsche is speeding along at 40 m/s (mph) and the Civic is going half the speed at 20 m/s.