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2 years ago

8

A ball is thrown upward from the ground with an initial speed speed of 25 meters/second; at the same instant, a ball is dropped

from rest from a building 15 meters high. After how long will the balls be at the same height?

1 answer:

victus00 [196]2 years ago

7 0

At the speed of 15m/s of first ball

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The efficiency of conversion of glucose to ATP during glycolysis is approximately:

liraira [26]

Answer: approximately 50%

Explanation:

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2 years ago

For elliptical obits: the direction of the velocity of the satellite is _______________________ (always, seldom, never) perpendi

alexandr1967 [171]

Answer:

For elliptical orbits: seldom

For circular orbits: always

Explanation:

We start by analzying a circular orbit.

For an object moving in circular orbit, the direction of the acceleration (centripetal acceleration) is always perpendicular to the direction of motion of the object.

Since acceleration has the same direction of the force (according to Newton's second law of motion), this means that the direction of the force (the centripetal force) is always perpendicular to the velocity of the object.

So for a circular orbit,

the direction of the velocity of the satellite is always perpendicular to the net force acting upon the satellite.

Now we analyze an elliptical orbit.

An elliptical orbit correponds to a circular orbit "stretched". This means that there are only 4 points along the orbit in which the acceleration (and therefore, the net force) is perpendicular to the direction of motion (and so, to the velocity) of the satellite. These points are the 4 points corresponding to the intersections between the axes of the ellipse and the orbit itself.

Therefore, for an elliptical orbit,

the direction of the velocity of the satellite is seldom perpendicular to the net force acting upon the satellite.

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2 years ago

a ship travels a port p and travels 30 km due north. then it changes course and travels 20 km in a direction 30° east of north

liq [111]

When we represent what is given to us on a coordinate plane, we have a figure as shown in the attachment.

To find the distance between P and R, we have to find the Net Displacement of the ship (brown arrow in the figure).

For that, we use the rules for Vector addition.

We see that the first displacement $D_{1}$ = 30 km (blue arrow) is along the y-axis, but the second part of the ship's journey $D_{2}$ = 20 km (red arrow) is at an angle with reference to y-axis.

So, we first find the components of the red arrow along X and Y.

Component of $D_{2}$ along X-axis is given by $D_{2x} = D_{2} Sin 30$ = 10 km

Component of $D_{2}$ along Y-axis is given by $D_{2y} = D_{2} Cos 30$ = 17.32 km

We now add all the vectors along X and along Y separately.

Net Displacement along X $D_{netX} = 10 km$

Net Displacement along Y $D_{netY} = 30 + 17.32$ = 47.32 km

Now that we have the components of the net displacement along X and Y, we make use of Pythagorean Theorem to calculate the $D_{net}$

$D_{net} = \sqrt{D_{netX} ^{2} + D_{netY} ^{2}}$

Therefore, [tex]D_{net} = 48.37 km.

Hence, the distance between the ports P and R is 48 km.

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2 years ago

Hicham El Guerrouj of Morocco holds the world record in the 1500 m running race. He ran the final 400 m in a time of 51.9 s.

konstantin123 [22]

Answer: His average speed in mph over the last 400 m is 7.7 m/s.

Explanation:

Given: Hicham El Guerrouj of Morocco holds the world record in the 1500 m running race. He ran the final 400 m in a time of 51.9 s.

We know that , speed = $\dfrac{distance}{time}$

Here , distance = 400m and time = 51.9 s

Then, speed = $\dfrac{400}{51.9}\approx7.7\ m/s$

Hence, his average speed in mph over the last 400 m is 7.7 m/s.

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2 years ago

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Answer:

mhm

Explanation:

The answer is c 00.095

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2 years ago