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2 years ago

A weight lifter lifts a 1.0 x 102 kg mass 1.5 m in 2.0 s. The power is?

Physics

1 answer:

Serga [27]2 years ago

6 0

Answer:

$\boxed{p = {7.4 \times 10}^{2} W} \to \: option \: c.$

Explanation:

$his \: power \: is \to \\ p = \frac{mgh}{t} \\ p = \frac{1.0 { \times 10}^{2} \times 1.5 \times 9.8}{2.0} \\ p= 735 \\ \boxed{p = {7.4 \times 10}^{2} }$

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Question 7 of 25

tiny-mole [99]

Answer:

2PBr₃ + 3Cl₂ → 2PCl₃ + 3Br₂

2Na + MgCl₂ → 2NaCl + Mg

Explanation:

A balanced chemical equation is a chemical equation that have an equal number of elements of each type on both sides of the equation

Among the given chemical reactions, we have;

2PBr₃ + 3Cl₂ → 2PCl₃ + 3Br₂

In the above reaction;

The number of phosphorus, P, on either side of the equation = 2

The number of bromine atoms, Br, on either side of the equation = 6

The number of chlorine atoms, Cl, on either side of the equation = 6

Therefore, the number of elements in the reactant side and products side of the reaction are equal and the reaction is balanced

The second balanced chemical reaction is 2Na + MgCl₂ → 2NaCl + Mg

In the above reaction, there are two sodium atoms, Na, one magnesium atom and two chlorine atoms on both sides of the reaction, therefore, the reaction is balanced

6 0

2 years ago

A baseball player hits a homerun, and the ball lands in the left field seats, which is 103m away from the point at which the bal

Sati [7]

(a) The ball has a final velocity vector

$\mathbf v_f=v_{x,f}\,\mathbf i+v_{y,f}\,\mathbf j$

with horizontal and vertical components, respectively,

$v_{x,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\cos(-38^\circ)\approx16.2\dfrac{\rm m}{\rm s}$

$v_{y,f}=\left(20.5\dfrac{\rm m}{\rm s}\right)\sin(-38^\circ)\approx-12.6\dfrac{\rm m}{\rm s}$

The horizontal component of the ball's velocity is constant throughout its trajectory, so $v_{x,i}=v_{x,f}$ , and the horizontal distance x that it covers after time t is

$x=v_{x,i}t=v_{x,f}t$

It lands 103 m away from where it's hit, so we can determine the time it it spends in the air:

$103\,\mathrm m=\left(16.2\dfrac{\rm m}{\rm s}\right)t\implies t\approx6.38\,\mathrm s$

The vertical component of the ball's velocity at time t is

$v_{y,f}=v_{y,i}-gt$

where g = 9.80 m/s² is the magnitude of the acceleration due to gravity. Solve for the vertical component of the initial velocity:

$-12.6\dfrac{\rm m}{\rm s}=v_{y,i}-\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)\implies v_{y,i}\approx49.9\dfrac{\rm m}{\rm s}$

So, the initial velocity vector is

$\mathbf v_i=v_{x,i}\,\mathbf i+v_{y,i}\,\mathbf j=\left(16.2\dfrac{\rm m}{\rm s}\right)\,\mathbf i+\left(49.9\dfrac{\rm m}{\rm s}\right)\,\mathbf j$

which carries an initial speed of

$\|\mathbf v_i\|=\sqrt{{v_{x,i}}^2+{v_{y,i}}^2}\approx\boxed{52.4\dfrac{\rm m}{\rm s}}$

and direction θ such that

$\tan\theta=\dfrac{v_{y,i}}{v_{x,i}}\implies\theta\approx\boxed{72.0^\circ}$

(b) I assume you're supposed to find the height of the ball when it lands in the seats. The ball's height y at time t is

$y=v_{y,i}t-\dfrac12gt^2$

so that when it lands in the seats at t ≈ 6.38 s, it has a height of

$y=\left(49.9\dfrac{\rm m}{\rm s}\right)(6.38\,\mathrm s)-\dfrac12\left(9.80\dfrac{\rm m}{\mathrm s^2}\right)(6.38\,\mathrm s)^2\approx\boxed{119\,\mathrm m}$

6 0

2 years ago

22. A ball is thrown horizontally from the roof of a building 12 m tall with a speed of 3.1 m/s.

zysi [14]

Answer:

a) t = 1.6 s

b) d = 4.9 m

c) v = 16 m/s

d) θ = 79°

Explanation:

time of fall

t = √(2h/g) = √(2(12)/9.8) = 1.5649... s

d = vt = 3.1(1.56) = 4.8512...

vertical velocity vy = at = 9.8(1.56) = 15.336... m/s

v = √(15.336² + 3.1²) = 15.6464... m/s

θ = arctan(15.336/3.1) = 78.5724...°

5 0

2 years ago

The picture below shows the setup for an experiment involving a 1000 mL beaker, sitting on a burner, filled with 500 mL of water

Vlad1618 [11]

Answer:

bye

Explanation:

bye

4 0

2 years ago

Which temperature scale has the highest value for the boiling point of water?

drek231 [11]

Answer: The correct answer is kelvin.

Explanation:

The expression for the conversion of degree Celsius to Kelvin is as follows:

K= 273 + degree Celsius

The expression for the conversion of degree Celsius to Fahrenheit is as follows:

$F=(Degree Celsius\times \frac{9}{5})+ 32$

The freezing point of water on Celsius degree is zero degree Celsius. The freezing point on kelvin scale is 273.15 K.

The boiling point of water on Celsius degree is 100 degree Celsius. The boiling point on kelvin scale is 373.15 K. The boiling point on Fahrenheit scale is 373.15 K.

Therefore, Kelvin scale has the highest value for the boiling point of water.

6 0

2 years ago