An explanation of sound<span> waves. The pitch of a </span>sound<span> is dictated by the frequency of the </span>sound<span> wave, while the loudness is dictated by the </span>amplitude<span>. When a drum is beaten, the air particles around the drum skin vibrate in the form of a compression wave</span>
Using the equation:
Energy transferred = Charge x Potential difference
Rearrange for p.d:
V = E/Q
Substitute values:
V = 80/20
V = 4
If the elevator was stationary, the scale would read exactly the weight of the person:

However, the elevator is moving with an acceleration a, so the scale reads a new value of the weight, which we call W'. Newton's second law becomes

where a' is actually the total acceleration of the person, so it's the sum of the acceleraion of the elevator and of the gravitational acceleration:

Taking the direction of g (downward) as the positive direction, we can find the value of a:


So, the acceleration of the elevator is

, with same sign of g, so it's directed downward as well.
<span>particle varies with time as shown in the diagram. ... resultant has a magnitude equal to 8.0. .... A constant force F is applied to a body of mass m that initially is headed east at velocity .... If the resultant force acting on a 2.0-kg object is equal to ..... A ball of mass mB is released from rest and acquires velocity of magnitude vB ...</span><span>
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