Why must you repeat steps three and four in the scientific method

How much force is needed to produce an acceleration of 20ms^2 in a body of mass 500gm

What is an neutral atom?

Which statement best describes the geocentric theory? A) The Earth and planets revolve around the sun. B) The stars form concentric spheres around the sun. C) All celestial bodies revolve around the Earth.

Which of the following describes the measure of the flow of electrical charge? A. watts B. volts C. Ohms D. amperes

Which of the following statements about the rings of the four jovian planets is not true? a. All rings lie within their planet's Roche zone b. All the particle orbits are fairly circular, near their planet's equatorial plane c.

Steam moves into a cylinder of a steam engine at a constant pressure and does 2.34 J of work on a piston. The diameter of the piston is 3.4 cm and the piston travels 4.6cm. What is the pressure of the steam?

Identify each type of simple machine.

A car's speedometer reads 20 m/s after accelerating, from a standing start, for 25s. What was the magnitude of its acceleration?

What happens to the period of a pendulum and the period of a spring as the amplitude of the oscillation increases? Briefly give an explanation for this relationship.

The element that is most abundant in earth is