The number of protons in the nucleus of an atom, which is characteristic of a chemical element and determines its place in the periodic table.
Denoted by letter Z
Explanation:
It is given that,
Length of the poster, l = 0.95 m
Breadth of the poster, b = 1 m
The poster is in the shape of rectangle. For a rectangular shape, perimeter is equal to :
P = 2(l+b)
P=2(0.95+1)
P=3.9 m
(b) One digits, P = 4 m
(c) Two digits, P = 3.9 m
(d) Three digits, P = 3.90 m
The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.
<h3>What is mechanical energy?</h3>
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
A boy is trying to roll a bowling ball up a hill. The friction is ignored. The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
M.E bottom of hill = M.E on top of hill
Kinetic energy + Potential energy = Kinetic energy + Potential energy
1/2 mu² + 0 = 0 + mgh
At the top of hill, the velocity will become zero. So, final kinetic energy is zero.
Substituting the values, we have
1/2 x u² = 9.8 x 22.5
u = sqrt [2 x9.8 x 22.5 ]
u= 21 m/s
Thus, the minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s.
Learn more about mechanical energy.
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