Potassium goes to argon so that a proton in the K nucleus "vanishes" into a positron (positive electron ?) but keeps the same atomic mass at 38. ? I'd say that the number of the positron was 0, and the charge was +1 electronic charge.
Answer:
A)F
B)F
C)T
Explanation:
A)
This is not always true that the product of the two vector's always non-negative .It may be positive or negative.
That is why this statement is false.
B)
The unit vectors in three perpendicular direction is i ,j and k.
We know that for unit vectors
i.i=j.j=k.k= 1
i .j= j.k=k.i=0
Therefore only parallel component of the force will contribute in the integral part instead of perpendicular component of the force.
That is why this statement is false.
C)
This statement is True.
A)F
B)F
C)T
Answer:
Explanation:
Before it hits the ground:
The initial potential energy = the final potential energy + the kinetic energy
mgH = mgh + 1/2 mv²
gH = gh + 1/2 v²
v = √(2g (H - h))
v = √(2 * 9.81 m/s² * (0.42 m - 0.21 m))
v ≈ 2.0 m/s
When it hits the ground:
Initial potential energy = final kinetic energy
mgH = 1/2 mv²
v = √(2gH)
v = √(2 * 9.81 m/s² * 0.42 m)
v ≈ 2.9 m/s
Using a kinematic equation to check our answer:
v² = v₀² + 2a(x - x₀)
v² = (0 m/s)² + 2(9.8 m/s²)(0.42 m)
v ≈ 2.9 m/s
