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3 years ago

Which of the following is an example of proper movement for a biceps curl?

Physics

1 answer:

DanielleElmas [232]3 years ago

5 0

<span>i think the answer is : Bend the arm at the elbow with the back straight </span>

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What causes an electric current in a wire?

nexus9112 [7]

The correct answer is B. Electrons flow because of electrical attraction and repulsion.

7 0

4 years ago

A high-speed K0 meson is traveling at β = 0.90 when it decays into a π + and a π − meson. What are the greatest and least speeds

san4es73 [151]

Answer:

greatest speed=0.99c

least speed=0.283c

Explanation:

To solve this problem, we have to go to frame of center of mass.

Total available energy fo π + and π - mesons will be difference in their rest energy:

$E_{0,K_{0} }-2E_{0,\pi } =497Mev-2*139.5Mev\\$

=218 Mev

now we have to assume that both meson have same kinetic energy so each will have K=109 Mev from following equation for kinetic energy we have,

K=(γ-1) $E_{0,\pi }$

$K=E_{0,\pi}(\frac{1}{\sqrt{1-\beta ^{2} } } -1)\\\frac{1}\sqrt{1-\beta ^{2} }}=\frac{K}{E_{0,\pi}}+1\\ {1-\beta ^{2}=\frac{1}{(\frac{K}{E_{0,\pi}}+1)^2}}\\\beta ^{2}=1-\frac{1}{(\frac{K}{E_{0,\pi}}+1)^2}}\\\beta = +-\sqrt{\frac{1}{(\frac{K}{E_{0,\pi}}+1)^2}}\\\\\\beta =+-\sqrt{1-\frac{1}{(\frac{109Mev}{139.5Mev+1)^2}}$

$u'=+-0.283c$

note +-=±

To find speed least and greatest speed of meson we would use relativistic velocity addition equations:

$u=\frac{u'+v}{1+\frac{v}{c^{2} } } u'\\u_{max} =\frac{u'_{+} +v_{} }{1+\frac{v}{c^{2} } } u'_{+} \\u_{max} =\frac{0.828c +0.9c }{1+\frac{0.9c}{c^{2} } } 0.828\\ u_{max} =0.99c\\u_{min} =\frac{u'_{-} +v_{} }{1+\frac{v}{c^{2} } } u'_{-}\\u_{min} =\frac{-0.828c +0.9c }{1+\frac{0.9c}{c^{2} } } -0.828c\\u_{min} =0.283c$

6 0

3 years ago

At noon, the temperature was 12º. it rose 8º during the afternoon, and then dropped 28º by midnight. what was the temperature at

djverab [1.8K]

At midnight, the temperature was -8 degrees.

7 0

3 years ago

Read 2 more answers

he potential energy between two atoms in a particular molecule has the form U(s) = 2.6/x^8 - 4.3/x^4 where the units of x are le

qwelly [4]

Answer:

x = 1.04866

Explanation:

Force can be defined from power energy by the expressions

F = $- \frac{ dU}{ dx}$

in this case we are the expression of the potential energy

U = $\frac{2.6}{x^{8} } - \frac{4.3}{ x^{4} }$

let's find the derivative

dU / dx = 2.6 ( $\frac{-8}{x^{9} }$ ) - 4.3 ( $\frac{-4}{ x^{5} }$ )

dU / dx = $- \frac{20.8}{ x^{9} } + \frac{17.2 }{ x^{5} }$

we substitute

F = + \frac{20.8}{ x^{9} } - \frac{17.2 }{ x^{5} }

at the equilibrium point the force is zero, so

$\frac{20.8}{ x^{9} } = \frac{17.2}{ x^{5} }$

20.8 / 17.2 = x⁴

x⁴ = 1.2093

x = $\sqrt[4]{ 1.2093}$

x = 1.04866

4 0

3 years ago

How do I solve number 2? Can someone please help?

Zigmanuir [339]

The rock is kicked horizontally off the cliff at 20 m/s.

There's no air resistance, and gravity has no effect on horizontal motion. There's no horizontal force acting on the rock to make it move horizontally slower or faster than 20 m/s, so it keeps moving horizontally at 20 m/s.

It's in the air for 7 seconds before it hits the ground. Moving horizontally at 20 m/s for 7 seconds, it sails (20 x 7) = 140 meters horizontally away from the cliff.

5 0

4 years ago