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3 years ago

Help me answer this please!

Physics

1 answer:

Westkost [7]3 years ago

3 0

Answer:

Option iv

Explanation:

The acceleration due to gravity (g) of the earth is constant (i.e 9.81 ms¯²). As long as the stone remains within the earth, the acceleration due to gravity experienced by the stone will be 9.81 ms¯².

The maximum height reached by an object is the height where the object no longer have velocity to move further hence it begins to fall back. At this point (i.e at the maximum height), the velocity of the object is zero.

Summary:

At maximum height:

Acceleration due to gravity of the stone = 9.81 ms¯²

Velocity = 0

Thus, option iv gives the correct answer.

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The siren on an ambulance emits a sound of frequency 2.80×103Hz. If the ambulance is traveling at 26.0 m/s (93.6 km/h or 58.2 mi

Norma-Jean [14]

To solve this problem it is necessary to apply the concepts related to the described wavelength through frequency and speed. Mathematically it can be expressed as:

$\lambda = \frac{v}{f}$

Where,

$\lambda =$ Wavelength

f = Frequency

v = Velocity

Our values are given as,

$f = 2.8*10^3Hz$

$v = 340m/s \rightarrow$ Speed of sound

Keep in mind that we do not use the travel speed of the ambulance because we are in front of it. In case it approached or moved away we should use the concepts related to the Doppler effect:

Replacing we have,

$\lambda = \frac{340}{2.8*10^3}$

$\lambda = 0.1214m$

Therefore the frequency that you hear if you are standing in from of the ambulance is 0.1214m

5 0

3 years ago

Why do aeroplanes take longer to fly west than east?

PolarNik [594]

Every planet/moon has global wind that are mostly determined by the way the planet/moon rotates and how evenly the Sun illuminates it. On the Earth the equator gets much more Sun than the poles. resulting in warmer air at the equator than the poles and creating circulation cells (or "Hadley Cells") which consist of warm air rising over the equator and then moving North and South from it and back round.

The Earth is also rotating. When any solid body rotates, bits of it that are nearer its axis move slower than those which are further away. As you move north (or south) from the equator, you are moving closer to the axis of the Earth and so the air which started at the equator and moved north (or south) will be moving faster than the ground it is over (it has the rotation speed of the ground at the equator, not the ground which is is now over). This results in winds which always move from the west to the east in the mid latitudes.

8 0

3 years ago

Calculate the speed of a car that traveled 200 kilometers in 3 hours.

nignag [31]

Answer:

The units (km/h) tell you how to do this! 200km/3h = 66.66666666…. BUT technically you only have ONE significant digit: 3 so 66.666… rounded to ONE digit is 70km/h but that is probably not important in this intro class so V = 66.67 or 67 km/h

8 0

3 years ago

Read 2 more answers

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

Sonbull [250]

Question 1

In order to do work, the force vector must be

in the same direction as the displacement vector and the motion.

Question 2

In which of the following cases is work being done on an object?

Pulling a trailer up a hill

Question 3

Which situation is an example of NOT doing work?

carrying a box

Question 4

Work is measured in

Joules

Question 5

To find the work done, the force exerted and distance moved are multiplied. A couch is moved twice before you are happy with its placement. The same force was used to move the couch both times. If more work is done the first time it is moved, what do you know about the distance it was moved?

When more work was done, the couch was moved further.

Question 6

A weight lifter raises a 1600 N barbell to a height of 2.0 meters. How much work was done? W = Fd

3200 Joules

Question 7

You and a friend (Alex) are at a a tree-top adventure park .. . . part of the course requires you to climb up a rope. You both climb the same rope in the same amount of time. However, the tension in the rope is greater

when Alex climbs. Who did the most work?

Alex did - more tension means more force - more force means more work was done

Question 8

Doing work at a faster rate creates power.

more

Question 9

In one challenge on the Titan Games, competitors have to lift 200 pounds up a long ramp. Angel is able to move the weight in 42 seconds. Anthony gets it done in only 38 seconds. Which statement is true?

Anthony has more power than Angel.

Question 10

A mountain climber exerts 41,000 J of work to climb a cliff. How much power does the climber need if she wants to finish in only 500 seconds? Power = Work / time

82 Watts

Question 11

Your family is moving to a new apartment. While lifting a box 83 Joules of work is done to put the box on a truck, you exert an upward force of 75 N for 3 s. How much power is required to do this? (Hint: You only need two of the 3 numbers given!) Power = Work / time

27.7 Watts

<em>*100% CORRECT ANSWERS</em>

4 0

3 years ago

Two sets of Christmas lights are available. For set A, when one bulb is removed, the remaining bulbs remain illuminated. For set

Paul [167]

Explanation:

Bulbs are nothing but resistors that glow when current passes through them.

In Set A, the bulbs (resistors) are connected parallely to each other, this means that even if one of the bulbs fuses or removed, the circuit will still be completed and others continue to glow.

And in parallel connection if the resistance of the two resistors are same powered delivered to each is same.

In Set B, bulbs are in series connection, this means that when one of the bulb is removed or fuses, the circuit will break and other bulbs can not operate.In this situation as well if the resistance of two resistors is same then the power delivered is same.

7 0

3 years ago