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2 years ago

PLEASE USE KINEMATIC EQUATION!

Physics

1 answer:

valkas [14]2 years ago

5 0

At its maximum height h, the football has zero vertical velocity, so if it was kicked with initial upward speed v, then

0² - v² = -2gh

Solve this for v :

v² = 2gh

v = √(2gh)

The height y of the football t seconds after being kicked is

y = vt - 1/2 gt²

Substitute v = √(2gh), replace y = h, and solve for h when t = 3.8 s :

h = √(2gh) t - 1/2 gt²

h = √(2gh) (3.8 s) - 1/2 g (3.8 s)²

h ≈ (16.8233 √m) √h - 70.756 m

(By √m, I mean "square root meters"; on its own this quantity doesn't make much physical sense, but we need this to be consistent with √h. h is measured in meters, so √h is measured in √m, too.)

h - (16.8233 √m) √h + 70.756 m = 0

Use the quadratic formula to solve for √h :

√h = ((16.8233 √m) ± √((16.8233 √m)² - 4 (70.756 m))) / 2

Both the positive and negative square roots result in the same solution,

√h ≈ 8.411 √m

Take the square of both sides to solve for h itself:

(√h)² ≈ (8.411 √m)²

⇒ h ≈ 70.756 m ≈ 71 m

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Name any two liquid which are found in our human eyes

Romashka [77]

Aqueous humor and vitreous humor are the liquids present in the human eye.

Hope it helped you... pls mark brainliest

8 0

3 years ago

Radio waves travel at 3.00 · 108 m/s. Calculate the wavelength of a radio wave of frequency 900 kHz. (9.00 · 105 Hz.)

Anuta_ua [19.1K]

V: velocity of wave
f: frequency
L: wavelenght

v = fL => L = v/f => L = (3x10^8)/(900x10^3) => L = 3.33 x 10^2m

7 0

3 years ago

If two objects A and B have the same kinetic energy but A has three times the momentum of B, what is the ratio of their inertias

Thepotemich [5.8K]

Answer:

$\frac{inertia_B}{inertia_A}=9$

Explanation:

First of all, let's remind that:

- The kinetic energy of an object is given by $K=\frac{1}{2}mv^2$ , where m is the mass and v is the speed

- The momentum of an object is given by $p=mv$

- The inertia of an object is proportional to its mass, so we can write $I=km$ , where k just indicates a constant of proportionality

In this problem, we have:

- $K_A = K_B$ (the two objects have same kinetic energy)

- $p_A = 3 p_B$ (A has three times the momentum of B)

Re-writing both equation we have:

$\frac{1}{2}m_A v_A^2 = \frac{1}{2}m_B v_B^2\\m_A v_A = 3 m_B v_B$

If we divide first equation by second one we get

$v_A = 3 v_B$

And if we substitute it into the first equation we get

$m_A (3 v_B)^2 = m_B v_B^2\\9 m_A v_B^2 = m_B v_B^2\\m_B = 9 m_A$

So, B has 9 times more mass than A, and so B has 9 times more inertia than A, and their ratio is:

$\frac{I_B}{I_A}=\frac{km_B}{km_A}=\frac{9m_A}{m_A}=9$

7 0

3 years ago

You drive on Interstate 10 from San Antonio to Houston, half the time at 75 km/h and the other half at 106 km/h. On the way back

r-ruslan [8.4K]

Answer:

Explanation:

a ) from San Antonio to Houston let distance be d km .

Average speed = total distance / total time

time = distance / speed

Total time = (d / 2 x 75 ) +( d / 2 x 106 )

= .0067 d + .0047 d

= .0114 d

Average speed = d / .0114 d = 87.72 km /h

b ) from Houston back to San Antonio

Total time = (d / 2 x 106 ) +( d / 2 x 75 )

= .0047 d + .0067 d

= .0114 d

Average speed = d / .0114 d = 87.72 km /h

c )

For entire trip :

total distance = 2d

total time = 2 x .0114 d

Average speed = 2 d / 2 x .0114 d

= 87.72 km /h .

4 0

3 years ago

Design an experiment to test the rate at which temperature changes for two different masses (amounts) of water.

mrs_skeptik [129]

Answer:Experimental Question: How does the amount of a substance affect the rate at which temperature changes?

It depends on the conductivity of the material. If the shift is extreme, the temperature near the heating / cooling source will be similar to the temperature of the heating / cooling source and it will take time for the remainder of the material to rise to temperature. It will depend on the conductivity of the material.

Hypothes is:

Materials List:

• digital stopwatch

• 250ml beaker

• rubber bung

• thermometer

• bunsen burner

• tripod

• gauze

• retort stand and clamp

• goggles

Safety Procedures *:

1. Adult supervision is required.

2. Wear safety goggles, apron, and closed-toe shoes.

3. Do not wear baggy sleeves or dangling jewelry. Tie long hair back.

4. Use hot pads or oven mitts to handle hot objects.

5. Do not reach over a hot burner.

6. Do not leave the experiment unattended.

7. Clean up spills immediately.

8. Report any injuries to your Learning Coach or adult supervisor immediately

Experimental Procedures :

• Fill an empty beaker with exactly 150ml of water (check side-scale of beaker)

• Set up apparatus as shown above. Ensure the thermometer is about 2cm above the bottom of the beaker.

• Light the bunsen burner and put on a blue flame. Heat up the water.

• When the temperature on the thermometer has reached 90°C, immediately switch off the burner.

• Start the stopwatch and time for 5.0 minutes.

• Read the thermometer value at the 5.0 minute mark.

• Before repeating the experiment, check the level of water is still 150ml

Data Table:

Start Temperature of Water (°C) Temperature after 5min (°C) Drop in Temperature

(°C) Average Rate of Cooling x 1000 (°C/s)

80 70 10 17

75 66 9 15

70 62 8 13

65 59 6 10

60 55 5 8

Analysis:

Conclusions : There is a strong correlation between the average rate of cooling and the start temperature: the greater the start temperature, the faster the average rate of cooling.

Explanation:

use quillbot or this will be considered plagerism

3 0

3 years ago