An element's atomic number is 39. How many protons would an atom of this element have?

What distance will a car traveling 65km/hr travel in 3 hours

What happens when a main-sequence star exhausts its core hydrogen fuel supply?

List all possible locations, situations gravity is absent

think about Newton's second law. when designing a rocket ship, what could be adjusted in the design to provide more acceleration?

A ball is kicked into the air at time t = 0. While the ball is in the air, its height above the ground after t seconds is - 16t^2 + 40t feet. How many seconds after the ball is kicked will it hit the ground?

A charge if 2 nC is placed 10cm to the right of a conducting sphere with a diameter of 2 cm. A charge of 5 nC is placed 10 nC to the left of the same sphere. determine the charge at the center of the sphere.

1) How is chemical energy transformed into potential energy?

A double-paned window has two glass panes separated by a layer of air. Why is air, rather than glass, used to fill this space?

To determine waves frequency you must know the what

What is the average speed in miles per hour of the car that traveled a total of 200 miles in 5.5 hours