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3 years ago

Which of the following is a chemical reaction? A. A spoon bending B. Wood burning C. Plates being stacked D. A book being opened

Physics

2 answers:

Flura [38]3 years ago

6 0

B. Wood buring is the answer

Anna [14]3 years ago

5 0

B. Wood burning
All the other choices don't make sense, it's just something physical lol

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Match the type of boundary with it's characteristic

vodomira [7]

Answer:

Transform= not destroyed or created

Divergent= crust created

Convergent= crust destroyed

Explanation:

The plates move in the opposite or away from each other at a transforming plate boundary. The two platform borders are not produced or destroyed in this case. As both plates converge on each other and thus destroy the plates for converging plate boundaries. When the plate is divergent, both plates shift away from each other by opening up and solidification for a new crust.

3 0

3 years ago

Read 2 more answers

Medical cyclotrons need efficient sources of protons to inject into their center. In one kind of ion source, hydrogen atoms (i.e

antoniya [11.8K]

Answer:

$r=5.278\times 10^{-4}\ m$

Explanation:

Given that:

magnetic field intensity, $B=0.07\ T$

kinetic energy of electron, $KE=1.2\ eV= 1.2\times 1.6\times 10^{-19}\ J= 1.92\times 10^{-19}\ J$

we have mass of electron, $m=9.1\times 10^{-31}\ kg$

<em>Now, form the mathematical expression of Kinetic Energy:</em>

$KE= \frac{1}{2} m.v^2$

$1.92\times 10^{-19}=0.5\times 9.1\times 10^{-31}\times v^2$

$v^2=4.2198\times 10^{11}$

$v=6.496\times 10^6\ m.s^{-1}$

<u>from the relation of magnetic and centripetal forces we have the radius as:</u>

$r=\frac{m.v}{q.B}$

$r=\frac{9.1\times 10^{-31}\times 6.496\times 10^6 }{1.6\times 10^{-19}\times 0.07}$

$r=5.278\times 10^{-4}\ m$

6 0

3 years ago

While visiting the beach, you enjoy the warm ocean water, but the sand burns your feet. That night you walk along the beach and

garik1379 [7]

The answer would be B..

Since sand can heat up quickly, it will also cool off quickly. But water takes a long time to heat up and cool down.

8 0

3 years ago

For a moving object, the force acting on the object varies directly with the object's acceleration. When a force of 81 N acts on

tensa zangetsu [6.8K]

Answer:

18 N

Explanation:

You have to do:

81 N: 9 ms2= x: 2 ms2

6 0

3 years ago

a mass of 0.75 kg is attached to a spring and placed on a horizontal surface. the spring has a spring constant of 180 N/m, and t

Artemon [7]

Answer:

6.57 m/s

Explanation:

First use Hook's Law to determine the F the compressed spring acts on the mass. Hook's Law F=kx; F=force, k=stiffnes of spring (or spring constant), x=displacement

F=kx; F=180(.3) = 54 N

Next from Newton's second law find the acceleration of the mass.

Newton's .2nd law F=ma; a=F/m ; a=54/.75 = 72m/s²

Now use the kinematic equation for velocity (or speed)

v₂²= v₀² + 2a(x₂-x₀); v₂=final velocity; v₀=initial velocity; a=acceleration; x₂=final displacement; x₀=initial displacment.

v₀=0, since the mass is at rest before we release it

a=72 m/s² (from above)

x₀=0 as the start position already compressed

x₂=0.3m (this puts the spring back to it's natural length)

v₂²= 0 + 2(72)(0.3) = 43.2 m²/s²

v₂= $\sqrt{43.2)\\$ = 6.57 m/s

5 0

3 years ago