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anyanavicka [17]
2 years ago
11

Explain how a thumbtack is designed so that you do not have to use a lot of force to push it through paper or the surface of a b

ulletin board?
Physics
1 answer:
Brums [2.3K]2 years ago
8 0
Thumbtacks have a flat top which gives you a bigger area to push on, and the end is tapered and sharp to make it easier to push it into a wall, etc.
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To increase the gravitational force between the two objects above, I could
egoroff_w [7]

Answer:

Option A

Explanation:

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2 years ago
What is the prefix for oxygen in As2O5? tri- di- mono- penta-
ikadub [295]
The prefix for oxygen in As2O5 is PENTA. 
Penta is used to show that the number of oxygen atoms present in the compound is five. Penta means five, while mono mean one, di means two, tri means three and tetra mans four and so on. The chemical name for the given compound is Arsenic pentoxide.
3 0
3 years ago
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What is the process called when a solid changes to a<br> liquid?<br><br> ???20 points?ASAP please
svp [43]

Answer:

melting

Explanation:

6 0
3 years ago
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Carbon is allowed to diffuse through a steel plate 15 mm thick. The concentrations of carbon at the two faces are 0.65 and 0.30
beks73 [17]

Answer:

T=575.16K

Explanation:

To solve the problem we proceed to use the 1 law of diffusion of flow,

Here,

J=-D\frac{\Delta C}{\Delta x}

\Delta C is the rate in concentration

\Delta xis the rate in thickness

D is the diffusion coefficient, where,

D= D_0 exp(\frac{Q_d}{RT})

Replacing D in the first law,

J=-(D_0 exp(\frac{-Q_D}{RT}))\frac{\Delta }{\Delta x}

clearing T,

T=\frac{Q_d}{R*ln(\frac{J*\Delta x}{D_0*\Delta C})}

Replacing our values

T=-\frac{80000}{8.31*ln(\frac{(6.2*10^{-7})(-15*10^{-3})}{(1.43*10^{-9})(0.65-0.30)})}

T=-\frac{80000}{-138.09}

T=575.16K

4 0
3 years ago
At a time t = 2.80 s , a point on the rim of a wheel with a radius of 0.230 m has a tangential speed of 51.0 m/s as the wheel sl
bonufazy [111]

Answer:

Part A) the angular acceleration is α= 44.347 rad/s²

Part B) the angular velocity is 195.13 rad/s

Part C)  the angular velocity is 345.913 rad/s

Part D ) the time is t= 7.652 s

Explanation:

Part A) since angular acceleration is related with angular acceleration through:

α = a/R = 10.2 m/s² / 0.23 m =   44.347 rad/s²

Part B) since angular acceleration is related

since

v = v0 + a*(t-t0) =  51.0 m/s + (-10.2 m/s²)*(3.4 s - 2.8 s) = 44.88 m/s

since

ω = v/R = 44.88 m/s/ 0.230 m = 195.13 rad/s

Part C) at t=0

v = v0 + a*(t-t0) =  51.0 m/s + (-10.2 m/s²)*(0 s - 2.8 s) = 79.56 m/s

ω = v/R = 79.56 m/s/ 0.230 m = 345.913 rad/s

Part D ) since the radial acceleration is related with the velocity through

ar = v² / R → v= √(R * ar) = √(0.23 m  * 9.81 m/s²)= 1.5 m/s

therefore

v = v0 + a*(t-t0) → t =(v -  v0) /a + t0 = ( 1.5 m/s - 51.0 m/s) / (-10.2 m/s²) + 2.8 s = 7.652 s

t= 7.652 s

4 0
3 years ago
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