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3 years ago

Juan rides his horse with a constant speed of 18 km/h. How far can he travel in 1/2 hour?

Physics

1 answer:

Brut [27]3 years ago

3 0

Answer:

He traveled 9km

Explanation:

To do this problem you need to use the equation which is Speed= distance/time and this problem gives you the speed which is 18 km/h and it gives you the time 1/2 hour so you write the equation 18= d/ 1/2 which his distance is 9km

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A bicycle rider pushes a 13kg bicycle up a steep hill. the incline is 24 degree and the road is 275m long. the rider pushes the

Digiron [165]

Answer:

A. W = 6875.0 J.

B. W = -14264.6 J.

Explanation:

A. The work done by the rider can be calculated by using the following equation:

$W_{r} = |F_{r}|*|d|*cos(\theta_{1})$

Where:

$F_{r}$ : is the force done by the rider = 25 N

d: is the distance = 275 m

θ: is the angle between the applied force and the distance

Since the applied force is in the same direction of the motion, the angle is zero.

$W_{r} = |F_{r}|*|d|*cos(0) = 25 N*275 m = 6875.0 J$

Hence, the rider does a work of 6875.0 J on the bike.

B. The work done by the force of gravity on the bike is the following:

$W_{g} = |F_{g}|*|d|*cos(\theta_{2})$

The force of gravity is given by the weight of the bike.

$F_{g} = -mgsin(24)$

And the angle between the force of gravity and the direction of motion is 180°.

$W_{g} = |mgsin(24)|*|d|*cos(\theta_{2})$

$W_{g} = 13 kg*9.81 m/s^{2}*sin(24)*275 m*cos(180) = -14264.6 J$

The minus sign is because the force of gravity is in the opposite direction to the motion direction.

Therefore, the magnitude of the work done by the force of gravity on the bike is 14264.6 J.

I hope it helps you!

3 0

3 years ago

What is Sonogram?Name one use of sonogram.

Blizzard [7]

Answer:

Sonogram is a medical image produced by ultrasound echo. 

It is used to help diagnose causes of pain and swelling. 

8 0

3 years ago

What is the approximate energy required to raise the temperature of 1.00 L of hydrogen by 90 °C? The pressure is held constant a

Oliga [24]

Answer:

Q = 116.8 J

Explanation:

Here given that the temperature of 1 L hydrogen is increased by 90 degree C at constant pressure condition.

So here we will have

$Q = n C_p \Delta T$

here we know that

n = number of moles

$n = \frac{1}{22.4}$

$n = 0.0446$

for ideal diatomic gas molar specific heat capacity at constant pressure is given as

$C_p = \frac{7}{2}R$

now we have

$Q = (0.0446)(\frac{7}{2}R)(90)$

$Q = 116.8 J$

3 0

3 years ago

You're using a monochromatic beam of light with wavelength 500 nm in an interferometer. What is the miminum distance you would n

Marina CMI [18]

Answer:

Minimum distance needed to move one of the mirrors = 125 nm

Explanation:

Constructive interference occurs when the maxima (trough or crest) of two waves that are in phase add together so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes.

Destructive interference occurs when the maxima (trough or crest) of two waves that are out of phase by 180⁰ or half a wavelength combine to produce a smaller amplitude than the individual amplitudes that combine. It can even produce a wave of zero amplitude.

Since the spot of constructive interference has been changed to destructive interference, Path difference = Wavelength/2

Path difference = 500nm/2 = 250 nm

Path difference = 250 * 10⁻⁹ m

Since there are two interferometer's mirrors and only one is moved, the minimum distance will be a half of the path difference.

That is, minimum distance = (path difference)/2

Minimum distance = (250 * 10⁻⁹)/2

Minimum distance = 125 * 10⁻⁹ m

Minimum distance = 125 nm

5 0

3 years ago

In addition to their remarkable top speeds of almost 60 mph, cheetahs have impressive cornering abilities. In one study, the max

Sav [38]

Answer:

the minimum value of the coefficient of static friction between the ground and the cheetah's feet is 1.94

Explanation:

Given that ;

the top speed of Cheetahs is almost 60 mph

In cornering abilities ; the maximum centripetal acceleration of a cheetah was measured to be = 19 m/s^2

The objective of this question is to determine the what minimum value of the coefficient of static friction between the ground and the cheetah's feet is necessary to provide this acceleration?

From the knowledge of Newton's Law;

we knew that ;

Force F = mass m × acceleration a

Also;

The net force $F_{net}$ = frictional force $\mu_k mg$