Answer:
23 m/s downward
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<em>Taking the downward direction as positive</em>
<u>We are given:</u>
Initial velocity of the marble (u) = 0 m/s
Time interval (t) = 2.3 seconds
Final velocity (v) = x m/s
<u>Solving for the Final velocity:</u>
<u>Acceleration of the Marble:</u>
We know that gravity will make the marble accelerate at a constant acceleration of 10 m/s
<u>Final velocity:</u>
v = u + at [First equation of motion]
x = 0 + (10)(2.3) [replacing the given values]
x = 23 m/s
Hence, after 2.3 seconds, the marble will move at a velocity of 23 m/s in the downward direction
Answer:
By altering the quantum interactions of the electrons in the atoms of a metal's atoms, scientists from the University of Leeds have generated magnetism in metals that aren’t normally magnetic.
Explanation:
Answer:
0.79 s
Explanation:
We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:
The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that 
Now, we find the acceleration:
Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:
Answer:
The sphere C carries no net charge.
Explanation:
- When brougth close to the charged sphere A, as charges can move freely in a conductor, a charge equal and opposite to the one on the sphere A, appears on the sphere B surface facing to the sphere A.
- As sphere B must remain neutral (due to the principle of conservation of charge) an equal charge, but of opposite sign, goes to the surface also, on the opposite part of the sphere.
- If sphere A is removed, a charge movement happens in the sphere B, in such a way, that no net charge remains on the surface.
- If in such state, if the sphere B (assumed again uncharged completely, without any local charges on the surface), is touched by an initially uncharged sphere C, due to the conservation of charge principle, no net charge can be built on sphere C.
