If a 20kg object is moved across the floor and the coefficient of friction is 0.255. What is the frictional force?

An excited hydrogen atom emits light with a wavelength of 486.4 nm to reach the energy level for which n = 2. In which principal quantum level did the electron begin?

What produces a magnetic field

What is the mass of a baseball that has a kinetic energy of 100 J and travel at 5 m/s

A trolley of mass 1000 kg moving at 10 m/s collides and hooks onto another identical trolley at rest. What is the velocity of both the trolleys together?

A solid cone is 10 cm high. where is its center of mass?

If you were told an atom was an ion, you would know the atom must have a

When a potential difference of 13 V is placed across a resistor, the current in the resistor is 1.4 a. What is the resistance of the resistor?

Person with a mass of50 kg jumps up from the earth with an acceleration of 20 newtons. what is his acceleration?

The electron are accelrated to a speed of 2.40*10^7 in 1.8*10^-9, the force experinced by an electron?

You are given two positively charged particles, of equal magnitude, separated by a distance, "d". What will happen to the force field between the two particles when "d" is doubled?