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3 years ago

If Johnny won a 300 meter race in 40 seconds, his speed would be ?

Physics

2 answers:

irina1246 [14]3 years ago

4 0

Formula: s = d/t

s = speed

d = distance

t = time

Solve using the values we are given.

s = 300/40

s = 7.5m/s

Best of Luck!

Jet001 [13]3 years ago

4 0

Answer:

7.5 m/s

Explanation:

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Light waves that cross from an air medium to a water medium will

il63 [147K]

C. change length and direction

Explanation:

The density of the material in which the light wave is travelling affects the speed of the wave. Different materials have different densities and they effect differently light waves which travel through them. Light waves may change direction at the boundary between two transparent materials, depending on material density. Density also impacts the speed of light. The denser the material, the slower light travels through it. The wavelength also decreases as light travels through the denser medium.

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2 years ago

Under the Neutrality Acts, all of the following conditions were agreed to except which?

solniwko [45]

Under the Neutrality Act, all of the following conditions were agreed to except America would provide aid to any nation attacked by Axis Powers. The correct option in regards to all the options given in the question is option"a". During the 1930's the United Nations Congress passed the Neutrality Act. It was passed keeping in mind the turmoil Europe and Asia were passing through during that time. Eventually the turmoil led to the starting of World War II. The Acts were modified several times and ultimately withdrawn when the United States ships were attacked by German submarines.

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3 years ago

You are watching an archery tournament when you start wondering how fast an arrow is shot from the bow. Remembering your physics

spayn [35]

Answer:

$v_0 = 3.53~{\rm m/s}$

Explanation:

This is a projectile motion problem. We will first separate the motion into x- and y-components, apply the equations of kinematics separately, then we will combine them to find the initial velocity.

The initial velocity is in the x-direction, and there is no acceleration in the x-direction.

On the other hand, there no initial velocity in the y-component, so the arrow is basically in free-fall.

Applying the equations of kinematics in the x-direction gives

$x - x_0 = v_{x_0} t + \frac{1}{2}a_x t^2\\63 \times 10^{-3} = v_0t + 0\\t = \frac{63\times 10^{-3}}{v_0}$

For the y-direction gives

$v_y = v_{y_0} + a_y t\\v_y = 0 -9.8t\\v_y = -9.8t$

Combining both equation yields the y_component of the final velocity

$v_y = -9.8(\frac{63\times 10^{-3}}{v_0}) = -\frac{0.61}{v_0}$

Since we know the angle between the x- and y-components of the final velocity, which is 180° - 2.8° = 177.2°, we can calculate the initial velocity.

$\tan(\theta) = \frac{v_y}{v_x}\\\tan(177.2^\circ) = -0.0489 = \frac{v_y}{v_0} = \frac{-0.61/v_0}{v_0} = -\frac{0.61}{v_0^2}\\v_0 = 3.53~{\rm m/s}$

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3 years ago

If an astronaut throws an object in space, the object’s speed will _____

BigorU [14]

The object's speed will not change.

In fact, after the astronaut throws the object, no additional forces will act on it (since the object is in free space). According to Newton's second law:
$\sum F=ma$
where the first term is the resultant of the forces acting on the body, m is the mass of the object and a its acceleration, we see that if no forces act on the object, then the acceleration is zero. Therefore, the acceleration of the object is zero, and its velocity remains constant.

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3 years ago

A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0-V battery in his car is

avanturin [10]

Answer: 22.6 hours

Explanation:

The power is the measure of the rate of energy.

In this problem, the 12.0 V battery is rated at 51.0 Ah, which means it delivers 51.0 A of current in a time of t = 1 h = 3600 s. The power delivered by the battery can be written as

$P=IV$