The mass number is the total number of protons and neutrons within an atom and since we know that the unknown element has 6 neutrons, we can simply subtract the number of neutrons from the mass number to get the number of protons.
17 - 6 = 11
There are 11 protons in this unknown element.
Extra:
The number of protons (+) and electrons (-) are equal in a neutral atom so since you know that there are 11 protons you also know that there are 11 electrons. On the periodic table, the element with 11 electrons is Na or Sodium.
Hope this helps! :)
Answer:
Explanation:
(a) The force of gravity is called an attractive force because it is the force (although weak) in which a planetary body or matter uses to attract an object towards itself.
(b) Yes, it does and the formula for force of gravity between any two object is
F = G
where m1 and m2 are masses of the first and second object respectively
r is the distance between the center of the two masses
G is the gravitational constant
Answer:
<h2>15.25 N</h2>
Explanation:
A force of
is acting on a wagon along the road. The wagon weights
. Acceleration of the wagon is given as
.
Consider the block as the system, the forces acting are Frictional force, Gravitational force, Normal reaction and External force applied by us.
Gravitational Force and Normal Reaction cancel out each other.
Net External Force = Mass of system/wagon
Acceleration of wagon

has a negative sign because it opposes the motion of the wagon.
∴ Frictional Force = 15.25 N