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3 years ago

NEED HELP THIS IS DUE IN 30 MINUTES

Physics

1 answer:

11111nata11111 [884]3 years ago

8 0

-- The total distance between the towns = 460 km.

-- For the first 3 hours, he travels at an average speed of 60 km/hr. During that time, he covers (60 km/hr) x (3 hrs) = 180 km.

-- At that point, he still has (460km - 180km) = 280 km to go.

-- If he drives that 280km at an average speed of 70 km/hr, it'll take him (280km)/(70km/hr) = 4 hrs to cover it.

-- His total time for the whole trip is (3 hours for the first part) + (4 hours for the last part) = <em>7 hours</em>.

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a 42.3 kg girl and a 7.93 kg sled are on the surface of a frozen lake, 15.0m apart and linked by a rope, but not moving yet. the

ycow [4]

Answer:

they meet from the girl's original position at: 2.37 (meters)

Explanation:

We need to use the Newton's law, exactly the second law that relate force, mass and acceleration as: $F=m*a$ with this we can get both accelerations; solving for acceleration $a=\frac{F}{m}$ . Now $a_{girl}=\frac{5.76}{42.3}=0.14 (m/s^{2})$ and $a_{sled}=\frac{5.76}{7.93}=0.73(m/s^{2})$ . Then knowing that they both travel at the same time and assuming that the distance among the girl and the sled is: 15.0-x, so, $x=\frac{1}{2}*a_{girl}*t^{2}$ and $15.0-x=\frac{1}{2}*a_{sled}*t^{2}$ , solving for the time we get: $t=\sqrt{\frac{2x}{a_{girl} } }$ and $t=\sqrt{\frac{2*(15.0-x)}{a_{sled} } }$ with this equations we solving for the x that is the distance between the girl and the sled after the apply the force and we get: $\sqrt{\frac{2x}{a_{girl}}} = \sqrt{\frac{2*(15.0-x)}{a_{sled} }$ . Finally we get: $\frac{x}{a_{girl} }=\frac{(15.0-x)}{a_{sled} }$ and replacing the values we have got: $\frac{x}{0.14} =\frac{(15.0-x)}{0.73}$ so $5.33*x=15-x$ so x=2.37 (meters).

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3 years ago

Which form of energy is equal to the sum of an object’s kinetic and potential energy?

Natali5045456 [20]

Answer:

Mechanical Energy

Explanation:

The sum of kinetic energy and potential energy of an object is its total mechanical energy.

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3 years ago

Consider an ideal gas at 27.0 degrees Celsius and 1.00 atmosphere pressure. Imagine the molecules to be uniformly spaced, with e

My name is Ann [436]

To solve the exercise it is necessary to keep in mind the concepts about the ideal gas equation and the volume in the cube.

However, for this case the Boyle equation will not be used, but the one that corresponds to the Boltzmann equation for ideal gas, in this way it is understood that

$PV =NkT$

Where,

N = Number of molecules

k = Boltzmann constant

V = Volume

T = Temperature

P = Pressure

Our values are given as,

$N = 1$

$k = 1.38*10^{-23}J/K$

$T = 27\°C = 27\°C + 273 = 300K$

$P = 1atm = 101325Pa$

Rearrange the equation to find V we have,

$V = \frac{NkT}{P}$

$V = \frac{1(1.38*10^{-23})(300K)}{101325Pa}$

$V = 4.0858*10^{-26}m^3$

We know that length of a cube is given by

$V = L^3$

Therefore the Length would be given as,

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$L = (4.0858*10^{-26})^{1/3}$

$L = 3.445*10^{-9}m$

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If you know the distance an object travels, and the time it takes to do so, you can determine the object's velocity. -- FALSE. Knowing the distance and time, you can figure out the object's speed. But if you don't also know the direction it's moving, then you can't say what its velocity is.

If an object moves at constant speed, it must also be moving at constant velocity. -- FALSE. Besides constant speed, it also needs to move in a straight line to have constant velocity. If it turns, its velocity changes, even if its speed doesn't.

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Objects with equal velocities definitely have equal speeds. -- TRUE. If their velocities are equal, then their speeds are equal AND they're moving in the same direction.

After laboring through this one, I'm wondering if there can possibly be any more ways to say the same thing.

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Answer:

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