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3 years ago

If Joe rides his bike for 15 minutes at 20 km/hour south, how far has he ridden? (Give the answer in km) Watch the units!

Physics

1 answer:

Virty [35]3 years ago

3 0

Answer:

Distance covered by Joe, d = 5 km

Explanation:

It is given that,

Speed of Joe, v = 20 km/hour

Time taken by Joe, t = 15 minutes = 0.25 h

We need to find the distance he is covering. It can be calculated using definition of speed as :

$v=\dfrac{d}{t}$

$d=v\times t$

$d=20\times 0.25$

d = 5 km

So, Joe covers a distance of 5 km. Hence, this is the required solution.

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Describes the relationship between the spectrum of one atom and the spectrum of another?

krok68 [10]

The relationship between the number of visible spectral lines are identical for atoms .However they have unique wavelengths.

Option B

Explanation:

A spectrum is a range of frequencies or a range of wavelengths. The photon energy of the emitted photon is equal to the difference between two states. For every atom there are quite many electron transitions and each has a energy difference.

This difference in wavelength causes spectrum .As each element emission spectrum is unique because each atom has different energy and causes uniqueness in the emission spectrum . Hence, due to the difference in energy it emits different wavelengths.

6 0

2 years ago

How much time would it take for the sound of thunder to travel 1500 meters if sound travels at a speed of 330 m/s

Elis [28]

Data given:

Δx=1500m

v=330m/s

t=?

Formula:

V=Δx/t

Solution:

t=1500m/330m/s

t=4.5s

7 0

3 years ago

She sights two sailboats going due east from the tower. The angles of depression to the two boats are 42o and 29o. If the observ

Reika [66]

Answer:

The boats are 934.65 feet apart

Explanation:

Given:

The angles of depression to the two boats are 42 degrees and 29 degrees

Height of the observation deck i = 1,353 feet

To Find:

How far apart are the boats (y )= ?

Solution:

Step 1 : Finding the value of x(Refer the figure attached)

We can use the tangent ratio to find the x value

$tan(42^{\circ}) = \frac{1353}{x}$

$x = \frac{1353}{tan(42^{\circ}) }$

x = 590.47 feet

Step 2 : Finding the value of z (Refer the figure attached)

$tan(29^{\circ}) = \frac{1353}{z }$

$z = \frac{1353}{tan(29^{\circ})}$

z = 1525.12 feet

Step 3 : Finding the value of y (Refer the figure attached)

y = z -x

y = 1525.12 - 590.47

y = 934.65 feet

Thus the two boats are 934.65 feet apart

3 0

3 years ago

A 0.80 kg object tied to the end of a 2.0 m string swings as a pendulum. At the lowest point of its swing, the object has a kine

devlian [24]

Answer:

3.32 m/s

Explanation:

From the law of conservation of energy, the sum of mechanical and kinetic energy should be equal to the 10 J given. Potential energy is given by mgh where m is mass, g is acceleration due to gravity and h is the height. For this case, $h= l(1-cos\theta)$ and l is string length, given as 2 m, \theta is given as 50 degrees. Kinetic energy is given by $0.5mv^{2}$ and it is this velocity that is unknown.

$10J=0.5\times 0.8kg\times v^{2}+ 0.8kg\times 9.81\times 2m(1-cos 50^{\circ})\\v\approx 3.32 m/s$

6 0

3 years ago

Couldn’t you technically make infinite speed by putting a car in a vacuum chamber? Since top speed it made by the amount of forc

kakasveta [241]

Answer:

Explanation:

For infinite speed to be achevied, one must have no sink of energy to spend. The source of entropy in this example, is the tires hitting the surface, producing heat and friction. Not to mention that you'd still need fuel to start the car, and an infinite tunnel or track, which would be impossible and speed up to process of energy loss through entropy quicker.

7 0

3 years ago