3 years ago

Does an athlete do work on a trophy as she lifts it overhead

Physics

1 answer:

bogdanovich [222]3 years ago

3 0

No she/he is doing work for her muscles

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Dmitrij [34]

Answer:

= 40 km/hr

Explanation:

<u>speed = distance / time</u>

= 22km / 0.55 hr.

= 40 km/hr

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Determine the time of flight for a projectile shot at an angle of 24 degrees and with aninitial velocity of 26 m/s.

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I need help on this to I have to get answer fast

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Albert's laboratory is filled with a constant uniform magnetic field pointing straight up. Albert throws some charges into this

guajiro [1.7K]

Answer:

$\vec{F}=qB(v_y \hat{i} - v_x\hat{j})$

Explanation:

The force excerted by a magnetic field on a charged particle is given by the Lorentz force:

$\vec{F} = q \vec{v} \times \vec{B}$

Lets consider the z-direction of our coordinate system the same direction of the magnetic field, that is:

$\vec{B} = B \hat{k}$

Let us consider that the velocity of a given particle is:

$\vec{v} = v_x\hat{i} + v_y \hat{j} + v_z \hat{k}$

Therefore, since k×k = 0

$\vec{v} \times \vec{B} = (v_x\hat{i} + v_y \hat{j} + v_z \hat{k}) \times B\hat{k}\\\vec{v} \times \vec{B} = (Bv_x \hat{i} \times\hat{k}) + (Bv_y \hat{j}\times\hat{k})$

And since i, j , k are a rigth hand system:

i × j = k

j × k = i

k × i = j --> i × k= -j

$\vec{v} \times \vec{B} = Bv_x (-\hat{j}) + Bv_y \hat{i} = Bv_y \hat{i} - Bv_x\hat{j}$

Threfore, if the particle has charge q and velocity v = (vx,vy,vz), the magnetic force it will feel will be

$\vec{F}=qB(v_y \hat{i} - v_x\hat{j})$

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3 years ago

an airplane maintains a speed of 567 km/h relative to the air it is flying through as it makes a tripto a city 780 km away to th

Vera_Pavlovna [14]

A ) v = 567 - 33 = 534 km/h
v = d / t ⇒ t = d / v
t = 780 km / 534 km/h = 1.46 h
b ) v = 567 + 33 = 600 km/h
t = 780 km / 600 km/h = 1.3 h
c ) v = (567² +33²) ^(1/2) = √320,400 = 566 km/h
t = 780 km/ 566 km/h = 1.378 h

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Delvig [45]

Answer:

Explanation:

The explanation or solution is given in the attach document

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4 years ago