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Sindrei [870]
3 years ago
7

A ball starts from rest. It rolls down a ramp and reaches the ground after 4 seconds. Its final velocity when it reaches the gro

und is 7.0 meters/second. The initial velocity of the ball is meters/second, and its acceleration is meters/second2. NextReset
Physics
2 answers:
Sidana [21]3 years ago
8 0

Answer:

0 and 1.75

Explanation:

Hunter-Best [27]3 years ago
3 0
If it starts at rest the initial velocity is 0.
For an acceleration, a, and time, t, the velocity is v=at. Since at t=4, v=7, then a=7/4=1.75m/s^2
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A photovoltaic panel of dimension 2 m × 4 m is installed on the roof of a home. The panel is irradiated with a solar flux of GS
Flura [38]

Answer:

(a) the electrical power generated for still summer day is 1013.032 W

(b)the electrical power generated for a breezy winter day is 1270.763 W

Explanation:

Given;

Area of panel = 2 m × 4 m, = 8m²

solar flux  GS = 700 W/m²

absorptivity of the panel, αS = 0.83

efficiency of conversion, η = P/αSGSA = 0.553 − 0.001 K⁻¹ Tp

panel emissivity , ε = 0.90

Apply energy balance equation to determine he electrical power generated;  

transferred energy + generated energy = 0

(radiation + convection) +  generated energy = 0

[\alpha_sG_s-\epsilon \alpha(T_p^4-T_s^4)]-h(T_p-T_\infty) - \eta \alpha_s G_s = 0

[\alpha_sG_s-\epsilon \alpha(T_p^4-T_s^4)]-h(T_p-T_\infty) - (0.553-0.001T_p)\alpha_s G_s

(a) the electrical power generated for still summer day

T_s = T_{\infty} = 35 ^oC = 308 \ k

[0.83*700-0.9*5.67*10^{-8}(T_p_1^4-308^4)]-10(T_p_1-308) - (0.553-0.001T_p_1)0.83*700 = 0\\\\3798.94-5.103*10^{-8}T_p_1^4 - 9.419T_p_1 = 0\\\\Apply \  \ iteration \ method \ to \ solve \ for \ T_p_1\\\\T_p_1 = 335.05 \ k

P = \eta \alpha_s G_s A = (0.553-0.001 T_p_1)\alpha_s G_s A \\\\P = (0.553-0.001 *335.05)0.83*700*8 \\\\P = 1013.032 \ W

(b)the electrical power generated for a breezy winter day

T_s = T_{\infty} = -15 ^oC = 258 \ k

[0.83*700-0.9*5.67*10^{-8}(T_p_2^4-258^4)]-10(T_p_2-258) - (0.553-0.001T_p_2)0.83*700 = 0\\\\8225.81-5.103*10^{-8}T_p_2^4 - 29.419T_p_2 = 0\\\\Apply \  \ iteration \ method \ to \ solve \ for \ T_p_2\\\\T_p_2 = 279.6 \ k

P = \eta \alpha_s G_s A = (0.553-0.001 T_p_2)\alpha_s G_s A \\\\P = (0.553-0.001 *279.6)0.83*700*8 \\\\P = 1270.763 \ W

3 0
3 years ago
<img src="https://tex.z-dn.net/?f=2.25%20%5Ctimes%2030" id="TexFormula1" title="2.25 \times 30" alt="2.25 \times 30" align="absm
Paraphin [41]
67.5 is the answer i believe!!
7 0
3 years ago
Read 2 more answers
A guy wire 1005 feet long is attached to the top of a tower. When pulled taut, it touches level ground 552 feet from the base of
trasher [3.6K]

Answer:

56.7°

Explanation:

Imagine a rectangle triangle.

The triangle has 3 sides.

One side is the height of the tower, let's name it A.

Another side is the distance from the base of the tower to the point where the waire touches the ground. Let's name that B.

Sides A and B are perpendicular.

The other side is the length of the wire. Let's name it C.

From trigonometry we know that:

cos(a) = B / C

Where a is the angle between B anc C, between the wire and the ground.

Therefore

a = arccos(B/C)

a = arccos(552/1005) = 56.7°

7 0
3 years ago
a conducting rod whose length is 25 cm is placed on a u-shaped metal wire that has a resistance of 8.0 ω . the wire and the rod
andreyandreev [35.5K]

Answer:

The current is I  =  1 A

The direction is anti-clockwise

Explanation:

The diagram for this question is shown on the first uploaded image

From the question we are told that

     the length of the conducting rod is L  = 25 \ cm =  \frac{25}{100}  =  2.5 \ m

     The resistance is  R = 8  \Omega

      The magnetic field is  B = 0.40\ T

        The speed of the rod is v = 6.0 m/s

The emf induced is

          \epsilon  = BLv

 substituting values we have

           \epsilon = 0.40 * 2.5 * 8

           \epsilon = 8V

From ohm law the induced current would be

      I  =  \frac{\epsilon}{R }

 substituting values we have

       I  =  \frac{8}{8 }      

       I  =  1 A

The direction anticlockwise this because according to lenze law the current due to change in magnetic field will act in the opposite direction of the  force causing the magnetic field to change

4 0
4 years ago
Write a hypothesis about the effects of magnetic and electric fields. Use the format of "if . . . then . . . because . . ." and
steposvetlana [31]

If the charged particle moves in the magnetic field or electric field, then it experiences  magnetic force or electric force because of its magnetic or electric properties.

<h3>What is magnetic field?</h3>

The magnetic field is the region of space where a charged object experiences magnetic force when it is moving.

When a charged particle such as an electron or proton moves inside a conductor, magnetic lines of force rotate around the particle. This relative motion causes the magnetic field to generate.

Thus, If the charged particle moves in the magnetic field or electric field, then it experiences  magnetic force or electric force because of its magnetic or electric properties.

Learn more about magnetic field.

brainly.com/question/14848188

#SPJ1

7 0
2 years ago
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