I beleive she isnt doing any work due to holding the box motionless, you must be exerting a force in the direction of the box motion. If she is just standing there holding the box their isn't no work becuase no distance has been covered. work = force = distance.
Answer:
7.2 cm
Explanation:
magnetic field, B = 0.301 T
speed, v = 7.92 x 10^5 m/s
mass, m = 4.39 x 10^-27 kg
q = 1.6 x 10^-19 C
The radius of singly changed ion is given by

where, m is the mass of ion, v be the speed of ion, B is the magnetic field and q be the charge

r = 0.072 m
r = 7.2 cm
Answer: 
Explanation:
Given
Radioactive material is found to decrease 40% of its original value in 
Sample at any time is given by

where, 
Put values

Taking natural logarithm both side

The Earth’s average orbital speed expressed in kilometers per hours is 107225.5 Km/hr and the mass of the sun is 2.58 x
Kg
<h3>
Relationship between Linear and angular speed</h3>
Linear speed is the product of angular speed and the maximum displacement of the particle. That is,
V = Wr
Where
Given that the earth orbits the sun at an average circular radius of about 149.60 million kilometers every 365.26 Earth days.
a) To determine the Earth’s average orbital speed, we will make use of the below formula to calculate angular speed
W = 2
/T
W = (2 x 3.143) / (365.26 x 24)
W = 6.283 / 876624
W = 7.2 x
Rad/hr
The Earth’s average orbital speed V = Wr
V = 7.2 x
x 149.6 x 
V = 107225.5 kilometers per hours.
b) Based on the information given in this question, to calculate the approximate mass of the Sun, we will use Kepler's 3rd law
M = (4
) / G
M = (4 x 9.8696 x 3.35 x
) / (6.67 x
x 7.68 x
<em>)</em>
<em>M = 1.32 x </em>
/ 51.226
M = 2.58 x
Kg
Therefore, the Earth’s average orbital speed expressed in kilometers per hours is 107225.5 Km/hr and the mass of the sun is 2.58 x
Kg
Learn more about Orbital Speed here: brainly.com/question/22247460
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