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baherus [9]
3 years ago
12

A person is standing on a spring bathroom scale on the floor of an elevator which is moving up and slowing down at the rate of 2

.1 m/s 2 . The acceleration of gravity is 9.8 m/s 2 . If the person’s mass is 77.6 kg, what does the scale read? Answer in units of n
Physics
2 answers:
Fittoniya [83]3 years ago
8 0

Answer:  

923.4 N

Explanation:

from the question we are given the following:

upward acceleration (a) = 2.1 \frac{m}{s^{2} }

downward acceleration (acceleration due to gravity (g)) =   9.8 \frac{m}{s^{2} }

mass (m) = 77.6 kg

the net acceleration is going to be the resultant of the upward and downward acceleration.

For the accelerations, let upward be positive and downward be negative

Therefore

net acceleration = g - (-a)  (note that the negative sign in front of "a"  (-a) is because the person was decelerating)

= 9.8 - (-2.1) = 11.9

now we can get the reading on the scale from F = m x a

F = 77.6 x 11.9 = 923.4 N

Alinara [238K]3 years ago
6 0

Answer:

923.44N

Explanation:

Obviously Fn cannot equal Fg since the elevator is moving up  

Where Fn is the force read on the scale

Fg is gravitational force=mg=77.6 x 9.8=760.48N

So we use this equation:  

Fnet = Fn - Fg  

ma = Fn - mg

77.6 x 2.1 = Fn – 760.48

162.96N = Fn – 760.48N  

923.44 N = Fn

The answer is 923.44 N

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(a) 3.9cm

(b) 1.66 x 10⁻⁸s

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Since the electron is moving in a circular path, the centripetal acceleration needed to keep it from slipping off is provided by the magnetic force. This force (F), according to Newton's second law of motion is given by,

F = m x a          --------------(i)

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m = mass of the particle

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a = v² / r          [v = linear velocity of particle, r = radius of circular path]

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F = m v²/ r             --------------------(ii)

The magnitude of the magnetic force on a moving charge in a magnetic field as stated by Lorentz's law is given by;

F = qvBsinθ          -------------(iii)

Where;

q = charge of the particle

v = velocity of the particle

B = magnetic field

θ = angle between the velocity and the magnetic field

<em>Combine equations (ii) and (iii) as follows;</em>

m (v² / r) = qvBsinθ         [divide both side by v]

m v / r = qBsinθ              [make r subject of the formula]

r = (m v) / (qBsinθ)              ---------(iv)

(a) From the question;

v = 1.48 x 10⁷m/s

B = 2.14mT = 2.14 x 10⁻³T

θ = 90°          [since the direction of velocity is perpendicular to magnetic field]

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