49. If an atom contains 13 protons, then it has (2.4)

a. 13 electrons. b. 26 electrons. c. 13 neutrons.

d. 26 neutrons,

Two carts with masses of 4.52 kg and 2.42 kg move toward each other on a frictionless track with speeds of 5.08 m/s and 3.58 m/s respectively. The carts stick together after colliding head-on. Find the final speed.

An airplane is flying with constant speed of 300 m/s along a horizontal circle with a radius of 15,000 m. if the lift force of the air on the wings is perpendicular to the wings, at what angle relative to the horizontal should the wings be banked?

The movement of thermal energy from a warmer object to a cooler object is called

A runner has an initial velocity of 4 meters per second. After 20 seconds, the runner's velocity is 6 meters per second. Which is the runner's acceleration?

Write down the addres of earth in as much detail as possible.

A plane is flying east at 135 m/s. The wind accelerates it at 2.18 m/s^2 directly northeast. After 18.0s, what is the magnitude of the displacement of the plane?

The same constant force, F, is applied to two blocks. The first block has a mass of M and the second block has a mass of 2M. Both blocks are initially at rest and the force acts on each of them for the same period of time, t.

Which of the following is an example of the strong nuclear force acting in an atom? A. A proton repelling a proton B. A neutron attracting a neutron C. A neutron repelling an electron D. An electron attracting a proton

Does the air in our atmosphere have mass?

Your instructor hands you a closed flask partly filled with room-temperature water. When you hold it, the heat transfer between your bare hands and the flask causes the water to boil. Quite impressive! How is this accomplished?