Answer:

Explanation:
Given that,
If the mass of a body is 15 kg and produced an 4.2 m/s², we need to find the acceleration if the mass is 10 kg and the same force is applied.
Force is given by :
F = ma
Since force is same

So, if the mass is 10 kg, acceleration is 
Answer:
441.45N
Explanation:
Weight = mass(kg) x acceleration (m/s^2)
Weight = 45kg x 9.81m/s^2=441.45N
Recall that weight =mass of the rock x gravitational force acting on the rock
Therefore, the rock will weigh = 441.45N
Answer:
Explanation:
An object is drop from a height, then it is in direction of gravity
g is +ve
When an object drop from a height, the initial velocity is 0,
U=0
Given that h=4.4×10^7m
V=?
g=9.81m/s^2
Then using equation of motion
V^2=U^2+2gh
V^2=0+2×9.81×4.4×10^7
V^2=86.33×10^7m/s
Take square root of both side
V=29381.63m/s
Now to km/s, divide by 1000
Since 1km=1000m
V=29.38km/s
The average current density in the wire is given by:

where I is the current intensity and A is the cross-sectional area of the wire.
The cross-sectional area of the wire is given by:

where r is the radius of the wire. In this problem,
, so the cross-sectional area is

and the average current density is

The best explanation of the observation of the researcher is that some of the energy is converted into thermal energy (option C).
<h3>How does energy transfer?</h3>
Energy, according to the law of conservation of energy, cannot be created nor destroyed but transformed.
According to this question, a researcher found that the amount of light energy produced in a neon lighted sign was less than the amount of electrical energy used.
This suggests that some of the energy is converted into thermal energy.
Learn more about energy at: brainly.com/question/1932868
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