a) Potential energy: 147 m [J]
The gravitational potential energy of an object is given by
where
m is its mass
is the acceleration of gravity
h is the height of the object above the ground
In this problem,
h = 15 m
We call 'm' the mass of the ball, since we don't know it
So, the potential energy of the ball at the top of the hill is
(J)
b) Velocity of the ball at the bottom of the hill: 17.1 m/s
According to the law of conservation of energy, in absence of friction all the potential energy of the ball is converted into kinetic energy as the ball reaches the bottom of the hill. Therefore we can write:
where
v is the final velocity of the ball
We know from part a) that
U = 147 m
Substituting into the equation above,
And re-arranging for v, we find the velocity:
Your answer is C) The speed of sound is higher in solids than in liquids.
Answer:
1
The mass of the Potassium-40 is 
2
The Dose per year in Sieverts is 
Explanation:
From the question we are told that
The isotopes of potassium in the body are Potassium-39, Potassium-40, and Potassium-
41
Their abundance is 93.26%, 0.012% and 6.728%
The mass of potassium contained in human body is 
per kg of the body
The mass of the first body is 
Now the mass of potassium in this body is mathematically evaluated as
substituting value
The amount of Potassium-40 present is mathematically evaluated as
0.012% * 0.024
The dose of energy absorbed per year is mathematically represented as
Where E is the energy absorbed which is given as 
Substituting value
The Dose in Sieverts is evaluated as
Answer:
D is not the a vector quantities
The answer you are looking for is B, hope this helps.
