Why gravitational force at the center og earth is zero

A sprinter set a high school record in track and field, running 200.0 m in 20.6 s. what is the average speed of the sprinter in kilometers per hour?

How long would it take for a sound impulse to travel through a copper rod 25 kilometers long? the speed of copper is 3,500 0.071 sec 0.14 sec 7.1 sec 140 sec

Astrophysicists believe the dominant hot spots in the cosmic background radiation should be about 1° in angular size if the universe is flat. What do experimental measurements of this angular size tell us?

Which of the following is a disadvantage associated with scientific advances? a. decreased urbanization b. increased energy efficiency c. increased waste production d. increased renewable resource use

A major process by which the Sun's energy is transported around the Earth system?

In the system you're inspecting the damper motor isn't working, You decide to see if the damper-postion sensor us sending the proper signal to the which then signals the damper motor. A. heating coil B. duckwork c. energy source D. controller

Which of the following statements does not describe the structure of an atom? a. An atom has a small, dense center called the nucleus. b. Inside the nucleus of an atom are protons and electrons. c. Protons are positively charged sub-atomic particles.

A. Which skill related fitness component is your strongest and weakest?

A 100 N box is placed on an inclined plane that makes a 30° angle with the horizontal. Calculate the component of gravitational force that acts down the inclined plane. A. 25 N B. 50 N C. 87 N D. 100 N

Approximately how many kelvins are equal to 60 c? a. 289k b. 323k c. 333k d. 413k