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4 years ago

PLS HELP!

Physics

1 answer:

erastovalidia [21]4 years ago

5 0

Answer:

The correct option is (c).

Explanation:

The electrostatic force between charges is given by :

$F=k\dfrac{q_1q_2}{r^2}$

Where

r is the distance between charges

If the distance between two electric charges is tripled, r' =3r

New force becomes,

$F'=k\dfrac{q_1q_2}{(3r)^2}\\\\F'=k\dfrac{q_1q_2}{9r^2}\\\\F'=\dfrac{1}{9}\times k\dfrac{q_1q_2}{r^2}\\\\F'=\dfrac{F}{9}$

So, the new force becomes 1/9 of the original force. The correct option is (c).

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Answer: 7260,39

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3 years ago

It is possible to convert radiant energy into electrical energy using photovoltaic cells. Assuming equal efficiency of conversio

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Answer:

Ultraviolet radiation would yield more electrical energy

Explanation:

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3 years ago

A. The potential energy stored in the compressed spring of a dart gun, with a spring constant of 62.00 N/m, is 0.940 J. Find by

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a. The spring is compressed by 0.174 m.

b. The vertical distance the dart travels from its position when the spring is compressed to its highest position is 9.6 m.

c. The horizontal velocity of the dart at that time is 13.74 m/s.

d. The horizontal distance from the equilibrium position at which the dart hits the ground is 19.236 m.

<h3>What is potential energy?</h3>

The energy by virtue of its position is called the potential energy.

a. Given is the potential energy stored in the compressed spring of a dart gun, with a spring constant of 62.00 N/m, is 0.940 J.

PE of spring = 1/2 kx²

Put the values, we get

P.E = 0.940 = 1/2 x 62 x²

x = 0.174 m

Thus, the spring is compressed by 0.174 m.

b. Given is a 0.010 kg dart is fired straight up.

The vertical height is find out by

0.940 J = (0.010 kg) (9.8 m/s²) h

h = 9.6 m

Thus, the vertical distance the dart travels from its position is 9.6 m

c. From the conservation of energy principle, total mechanical energy is conserved.

1/2 mv² =mgh

v = √2gh

Plug the values, we get

v = √2 x 9.8x 9.6

v = 13.74 m/s

Thus, the horizontal velocity is 13.74 m/s.

d. Time that dart spends in air, t = √2h/g

t = √(2x9.6)/9.81

t = 1.4 s

The horizontal distance from the equilibrium position at which the dart hits the ground.

Horizontal distance = (Velocity on x direction) x time

Horizontal distance = 13.74 m/s x 1.4s

Horizontal distance = 19.236 m

Thus, the horizontal distance is 19.236 m.

Learn more about potential energy.

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A maglev train can “float” because magnets in the bottom of the train and on the guideway...

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3 years ago

A car accelerates uniformly from rest and

miv72 [106K]

Answer:

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Explanation:

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$d=v_0t+\frac{1}{2}at^2$

This car is starting from rest, so v₀ = 0 m/s. Additionally, we have a = 9.2/9.7 m/s² and t = 9.7 s. Plugging these values into our equation:

$d=0t+\frac{1}{2}\left(\frac{9.2}{9.7}\right)(9.7)^2\\d=\frac{1}{2}(9.2)(9.7)\\d=4.6(9.7)\\d=44.62$

So, the car has travelled 44.62 m in 9.7 seconds - we want to know how many of the tire's <em>circumferences</em> fit into that distance, so we'll first have to calculate that circumference. The formula for the circumference of a circle given its diameter is $c=\pi{d}$ , which in this case is 47.8π cm, or, using π ≈ 3.14, 47.8(3.14) = 150.092 cm.

Before we divide the distance travelled by the circumference, we need to make sure we're using the same units. 1 m = 100 cm, so 105.092 cm ≈ 1.5 m. Dividing 44.62 m by this value, we find the number of revs is

$44.62/1.5\approx29.75$ revolutions

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3 years ago