What term refers to the part of a spacecraft that is occupied by the crew for takeoff and landing?

Which statement explains the similarity between momentum and kinetic energy of an object?

Anon25 [30]

Answer:B.

Both increase as the mass and velocity increase.

3 0

2 years ago

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You yell into a canyon. You hear the echo in 3 seconds. How long did the sound of your voice travel before bouncing off a cliff?

Lilit [14]

Answer:

The sound travelled 516 meters before bouncing off a cliff.

Explanation:

The sound is an example of mechanical wave, which means that it needs a medium to propagate itself at constant speed. The time needed to hear the echo is equal to twice the height of the canyon divided by the velocity of sound. In addition, the speed of sound through the air at a temperature of 20 ºC is approximately 344 meters per second. Then, the height of the canyon can be derived from the following kinematic formula:

$2\cdot h = v\cdot t$ (1)

Where:

$h$ - Height, measured in meters.

$v$ - Velocity of sound, measured in meters per second.

$t$ - Time, measured in seconds.

If we know that $v = 344\,\frac{m}{s}$ and $t = 3\,s$ , then the height of the canyon is:

$h = \frac{v\cdot t}{2}$

$h = \frac{\left(344\,\frac{m}{s} \right)\cdot (3\,s)}{2}$

$h = 516\,m$

The sound travelled 516 meters before bouncing off a cliff.

7 0

2 years ago

*A car is going through a dip in the road whose curvature approximates a circle of radius 150m. At what velocity will the occupa

Valentin [98]

Answer:

v= 14.85 m/s

Explanation:

When at the bottom of the dip, the only force that keeps the car in the circular trajectory, is the centripetal force.
This force is not a new force, is just the net force aiming to the center of the circle.
In this case, is just the difference between the normal force (always perpendicular to the surface, pointing upward) and the force that gravity exerts on the car (which is known as the weight), pointing downward.
So, we can write the following expression:

$F_{cent} = F_{n} - F_{g} (1)$

It can be showed that the centripetal force is related to the speed by the following expression:
$F_{cent} = m*\frac{v^{2}}{r} (2)$

The normal force, it is called the apparent weight, because it would be the weight as measured by a scale.
Replacing (2) in (1), and solving for Fn, we get:

$F_{n} = m*\frac{v^{2} }{r} + m*g (3)$

Now, we need to find the value of v that makes Fn, exactly 15% more than the weight m*g, so we can write the following equation:

$F_{n} = 1.15*F_{g} = m*\frac{v^{2}}{r} +F_{g} (4)$

Replacing Fg by its value, simplifying, and solving for v, we get:

$v = \sqrt{0.15*g*r} = \sqrt{9.8 m/s2*0.15*150m} = 14.85 m/s (5)$

3 0

2 years ago

Which figure represents the electric field lines of two positive point charges?

Naddik [55]

Electric field lines of positive charges are always radially outwards

So here all field lines must have tendency to move out radially as well as two field lines never intersects with each other

So here field lines also do not intersects with each other

So overall the figure C is perfectly representing the field lines of two positive charges as these lines are not intersecting and also originating from two positive charges.

So answer must be

<u><em>FIGURE C</em></u>

7 0

3 years ago

Three people, John, Paul, and George, stand on top of Garage A to carry out a physics experiment by tossing tennis balls off the

m_a_m_a [10]

Answer:

1) John's ball lands last.

2) All three have the same total energy

Explanation:

John's ball will land last because his ball was projected at the largest angle. This means that the ball will spend more time in the air when compared to the other balls.

The total energy in a projected particle is the sum of its kinetic energy (0.5mv^2) and its potential energy due to its height (mgh). The total kinetic energy can be as a result of both, or at times fully transformed to either of the energy. For example, at the maximum height, the kinetic energy of John's ball is zero and is fully transformed into potential energy due to that height, whereas George's ball will mostly posses kinetic energy and a little potential energy. The three ball are assumed to have the same properties and are projected with the same initial velocity. This means that they all have the same kinetic energy at the instance of projection which can then be transformed into potential energy, or maintained as a combination of both throughout the flight or simply transformed into potential energy, but the total energy is always conserved.

7 0

3 years ago