The unknown metal with a mass of 39.27 g is potassium with the symbol K.
The mass of an atom is due to protons and neutrons present in it.
The protons and neutrons are together present in the nucleus of an atom.
The mass of any element is given by its mass number whose formula is
Mass Number = Number of protons + Number of neutrons
In the given case 39 = Number of protons + Number of neutrons
The only element of the periodic table which satisfies the above equation is potassium because it has 19 protons and 20 neutrons.
Thus, the unknown metal with a mass of 39.27 g is potassium with the symbol K.
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Answer: His acceleration is -18.66m/s^2
Explanation:
Ok, the initial speed is 2.8m/s. (we can define the initial direction as the positive direction).
And he wants to stop, so he must accelerate in the opposite direction as the initial movement, then we would have:
a(t) = -A.
So we have a constant, and negative acceleration.
Now, if we want to find the velocity we must integrate over time, and we will get:
v(t) = -A*t + V0
where V0 is the initial velocity, we know that it is 2.8m/s, and t is the time in seconds.
Then the velocity is:
v(t) = -A*t + 2.8m/s.
Now we know that John is brought to rest in 0.15 seconds after he starts slowing down, this means that at t = 0.15 seconds, his velocity is equal to zero.
v(0.15s) = 0m/s = -A*0.15s + 2.8m/s
2.8m/s = A*0.15s
2.8m/s/0.15s = 18.66m/s^2 = A.
So his acceleration is -A, then we have that:
His acceleration is -18.66m/s^2
Answer:
Explanation:
F= m x a
a= = = = =
Hopefully, this is right!
it is true. the trajectory reaches the value of zero at the top
Work = force x distance
So 88x15 = work
1,320N/m = work