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3 years ago

If a football player collides with a goal post, what forces are at work?

1 answer:

7 0

When a footballer collides with the goal post, the forces at work are the action and reaction forces. The player will exert an action force on the goal post, and then a reaction force from the goal post will stop the player. The reaction force call will cause pain and even injury to the player.

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Dolphin echolocation is similar to ultrasound. Reflected sound waves

s344n2d4d5 [400]

Answer:

Waves with high frequencies have shorter wavelengths that work better than low frequency waves for successful echolocation.

Explanation:

To understand why high-frequency waves work better than low frequency waves for successful echolocation, first we have to understand the relation between frequency and wavelength.

The relation between frequency and wavelength is given by

λ = c/f

Where λ is wavelength, c is the speed of light and f is the frequency.

Since the speed of light is constant, the wavelength and frequency are inversely related.

So that means high frequency waves have shorter wavelengths, which is the very reason for the successful echolocation because waves having shorter wavelength are more likely to reach and hit the target and then reflect back to the dolphin to form an image of the object.

Thus, waves with high frequencies have shorter wavelengths that work better than low frequency waves for successful echolocation.

3 0

3 years ago

What changes would result in a decrease in the gravitational force between two objects? Check all that apply.

REY [17]

I'm sorry, it says check all that apply, however there are no choices given. You should edit, and add the multiple choice answers.

My Answer:

Well if the masses of two objects were both decreased, it would result in a decrease in the gravitational force. So I guess the two objects masses would need to be decreased.

4 0

3 years ago

In the 1920s what did Edmund hubble notice about the galaxies

zlopas [31]

Hubble noticed that the galaxies were moving away from us, which meant the universe was expanding.

This is why constellations change over time. In some years, the Big Dipper won't actually look like a dipper anymore.

5 0

3 years ago

Ngan has a weight of 314.5 N on Mars and a weight 833.0 N on Earth. What is Ngan's mass on Earth?

mr_godi [17]

Ngan's mass on earth is 85kg.

Ngan has a weight on Mars = 14.5 N

Ngan’s weight on Earth = 833.0 N

Ngan’s mass on Earth = ?

Fg,earth = mg(earth)

M = Fg,earth / g(earth)

M = 833.0 N / 9.8 m/s2

M = 85 kg

4 0

3 years ago

Read 2 more answers

I have a voltage source of 12V but a light that only burns at 5V. The lamp works on 18 mA. Calculate the resistance that you EXT

ratelena [41]

Answer:

The resistance that will provide this potential drop is 388.89 ohms.

Explanation:

Given;

Voltage source, E = 12 V

Voltage rating of the lamp, V = 5 V

Current through the lamp, I = 18 mA

Extra voltage or potential drop, IR = E- V

IR = 12 V - 5 V = 7 V

The resistance that will provide this potential drop (7 V) is calculated as follows:

IR = V

$R = \frac{V}{I} = \frac{7 \ V}{18 \times 10^{-3} A} \ = 388.89 \ ohms$

Therefore, the resistance that will provide this potential drop is 388.89 ohms.

7 0

3 years ago