Answer: 1687.5 N
Explanation:
From the second law of motion given by Newton, Force is the rate change of momentum.
Mass of the baseball, m = 0.15 kg
Initial velocity, (negative because direction of initial velocity is opposite to the final velocity)
Final velocity,
The duration of collision,
Force,
Hence, the value of force is 1687.5 N.
a)
b) 0.43 V
c) 0.44 %
Explanation:
a)
For a battery with internal resistance, the relationship between emf of the battery and the terminal voltage (the voltage provided) is
(1)
where
V is the terminal voltage
E is the emf of the battery
I is the current
r is the internal resistance
In this problem, we have two situations:
1) when ,
Using Ohm's Law, the current is:
2) when ,
Using Ohm's Law, the current is:
Now we can rewrite eq.(1) in two forms:
And we can solve this system of equations to find r, the internal resistance. We do it by substracting eq.(2) from eq(1), we find:
b)
To find the electromotive force (emf) of the solar cell, we simply use the equation used in part a)
where
V is the terminal voltage
E is the emf of the battery
I is the current
r is the internal resistance
Using the first set of data,
is the voltage
is the current
is the internal resistance
Solving for E,
c)
In this part, we are told that the area of the cell is
While the intensity of incoming radiation (the energy received per unit area) is
This means that the power of the incoming radiation is:
This is the power in input to the resistor.
The power in output to the resistor can be found by using
where:
is the resistance of the resistor
is the current on the resistor (found in part A)
Susbtituting,
Therefore, the efficiency of the cell in converting light energy to thermal energy is:
The fraction of radioisotope left after 1 day is , with the half-life expressed in days
Explanation:
The question is incomplete: however, we can still answer as follows.
The mass of a radioactive sample after a time t is given by the equation:
where:
is the mass of the radioactive sample at t = 0
is the half-life of the sample
This means that the mass of the sample halves after one half-life.
We can rewrite the equation as
And the term on the left represents the fraction of the radioisotope left after a certain time t.
Therefore, after t = 1 days, the fraction of radioisotope left in the body is
where the half-life must be expressed in days in order to match the units.
Learn more about radioactive decay:
#LearnwithBrainly
Answer:
Explanation:
It is given that,
Mass of Albertine, m = 60 kg
It can be assumed, the spring constant of the spring, k = 95 N/m
Compression in the spring, x = 5 m
A glass sits 19.8 m from her outstretched foot, h = 19.8 m
When she just reach the glass without knocking it over, a force of friction will also act on it. Using the conservation of energy for the spring mass system such that,
So, the coefficient of kinetic friction between the chair and the waxed floor is 0.101. Hence, this is the required solution.