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drek231 [11]
3 years ago
10

4. A weightlifter raises a mass mat a constant speed to a height h in time t. Which of the following

Physics
1 answer:
marishachu [46]3 years ago
3 0

Answer:

<h3>a. mgh</h3>

Explanation

The work done by the lifter is equal to its potential energy since he is covering a height and under the influence of gravity.

potential energy = mass * acceleration due to gravity * height

m is the mass

g is the acceleration due to gravity

h is the height

Hence the required workdone = PE = mgh

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Cam Newton can sprint 40 meters in 5.79 seconds! How fast can he run?<br> Show your work
Setler79 [48]

Speed=Distance/Time

Distance=40m,time=5.79seconds

S=40/5.79

=6.908m/s

6 0
3 years ago
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During which phase of the moon may a solar eclipse occur?
alex41 [277]

Answer:

New moon

Explanation:

A solar eclipse can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface.

4 0
3 years ago
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To stretch a certain nonlinear spring by an amount x requires a force F given by F = 40 x − 6 x 2 , where F is in Newtons and x
strojnjashka [21]

Answer:

64 J

Explanation:

The potential energy change of the spring ∆U = -W where W = work done by force, F.

Now W = ∫F.dx

So, ∆U = - ∫F.dx = - ∫Fdxcos180 (since the spring force and extension are in opposite directions)

∆U = - ∫-Fdx

=  ∫F.dx

Since F = 40x - 6x² and x moves from x = 0 to x = 2 m, we integrate thus, ∆U =  ∫₀²F.dx

=  ∫₀²(40x - 6x²).dx

=  ∫₀²(40xdx - 6x²dx)

=  ∫₀²(40x²/2 - 6x³/3)

=  ∫₀²(20x² - 2x³)

= [20x² - 2x³]₀²

= [(20(2)² - 2(2)³) - (20(0)² - 2(0)³)

= [(20(4) - 2(8)) - (0 - 0))

= [80 - 16 - 0]

= 64 J

5 0
3 years ago
Consider two children sitting on a merry-go-round, with one closer to the outer edge and one closer to the center. show answer N
dolphi86 [110]

Answer:

They both have the same angular speed.

Explanation:

The mathematical formula for angular speed is:

w=\frac{2\pi}{T}

where w is angular speed, 2\pi is a constant, and T is the period (the time it takes the marry-go-round to complete a lap).

What we can see from the formula is that, since the 2\pi does not change its value, the angular speed depends only on the period T.

In this case for both the children closer to the outher edge and for the children closer to the center, the time to complete a lap is the same, because the time does not depend on where they are sitting in the marry go round. This means that the period for both is the same.

Thus, since the period for both is the same, the angular speed given by

w=\frac{2\pi}{T} will also be the same

4 0
3 years ago
If a piece of iron is placed in pure nitrogen, nothing happens. If the in is exposed to air, it begins to rust. What conclusion
kari74 [83]
Based on this, you can tell that Iron(Fe) does not react with Nitrogen(N), but does with something in normal air. The element the Iron is reacting with Oxygen(O), and the compound that is formed is called iron oxide.
6 0
3 years ago
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