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4 years ago

What statement about the greenhouse effect is not true?

1 answer:

5 0

The so-called greenhouse effect is observed only in houses painted green, and even there, only between the hours of 2PM - 4PM local time on Thursday afternoon.

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First, you will investigate purely vertical motion. The kinematics equation for vertical motion (ignoring air resistance) is giv

AlladinOne [14]

Answer: It takes 2.85 seconds.

Explanation: according to the question, the kinematics equation for vertical motion is

$y(t) = y_{0} + v_{0} .t - \frac{1}{2} .gt^{2}$

y₀ is the initial postion and equals 0 because it is fired at ground level;

v₀ is the initial speed and eqauls 14m/s;

g is gravity and it is 9.8m/s²;

y(t) is the final position and equals 0 because it is when the pumpkin hits the ground;

Rewriting the equation, we have:

0 + 14t - $\frac{1}{2}.9.8.t^{2}$ = 0

14t - 4.9t² = 0

t(14 - 4.9t) = 0

For this equation to be zero,

t = 0 or

14 - 4.9t = 0

- 4.9t = - 14

t = $\frac{14}{4.9}$

t = 2.86

It takes 2.86 seconds for the pumpkin to hit the ground.

6 0

3 years ago

What are the 3 Laws of Newtonian Mechanics

Katyanochek1 [597]

In the first law, an object will not change its motion unless a force acts on it. In the second law, the force on an object is equal to its mass times its acceleration. In the third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction

7 0

3 years ago

Read 2 more answers

Agent Bond is standing on a bridge, 17 m above the road below, and his pursuers are getting too close for comfort. He spots a fl

faust18 [17]

Answer:

2 poles

Explanation:

We are told Agent Bond is standing on a bridge, 17 m above the road below.

Now, the bed of the truck is 1.5 m above the road.

It means the distance hewill need to fall = 17 - 1.5 = 15.5 m

acceleration due to gravity = 9.8 m/s²

Initial velocity = 0 m/s

Thus, to find the time, we will use the equation;

s = ut + ½at²

Plugging in the relevant values gives;

15.5 = 0 + ½9.8t²

Multiply through by 2 to give;

15.5 × 2 = 9.8t²

31 = 9.8t²

t² = 31/9.8

t = √(31/9.8)

t = 1.78 sec

We are told that he spots a flatbed truck approaching at 28 m/s and that the telephone poles are 22m apart.

Thus; The truck will pass the poles at a rate of; Velocity/distance between poles = 28/22 = 1.273 poles per second

Since, we got the time to be 1.78 seconds, then we can find the number of poles by multiplying it with the rate of poles per seconds.

Thus;

Number of poles = 1.78 second × 1.273 poles/ seconds = 2.27 poles

This is approximately 2 poles

6 0

3 years ago

Earth-orbiting astronauts feel weightless in space because _____. Choose all that apply. 1 point They are in free-fall motion. T

STALIN [3.7K]

Answer:

They are in free-fall motion.

Explanation:

The Earth orbiting astronauts are falling at an acceleration that is the same or greater than the acceleration due to gravity i.e., 9.81 m/s². If you are continuously falling at this rate then you will feel weightless.

This same effect is felt while going down in an elevator. When you down in an elevator you feel that you are lighter and feel that something is pushing you up. Earth-orbiting astronauts feel the same effect but the accelration is greater hence they feel weightless.

5 0

3 years ago

The energy of an electromagnetic wave changes proportionally to which

ozzi

Answer:

D. Frequency

Explanation:

The energy of an electromagnetic wave is proportional to frequency, mathematically it is expressed as;

E ∝ f

E = hf

where;

h is Planck's constant = 6.626 x 10⁻³⁴ Js

The equation above can also be expanded to;

$E = hf = h \frac{c}{\lambda}$

where;

c is speed of light = 3 x 10⁸ m/s

λ is the wavelength of the electromagnetic wave

Since the speed of light is constant, we can conclude that the energy of the electromagnetic wave is directly proportional to its frequency and inversely proportional to its wavelength.

Therefore, the correct option for direct proportionality is FREQUENCY

8 0

3 years ago