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3 years ago

Which electromagnetic radiation can be seen with the human eye

1 answer:

6 0

Answer:the human retina can only detect incident light that falls in waves 400 to 720 nano-meters long so we cant see microwave or ultraviolet wavelengths. this also applies to infrared lights which has wavelengths longer than visible and shorter than microwaves thus being invisible to the human eye

Explanation:

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A ball falls from the top of a building. As it falls, its speed increases. Which type of energy is the ball gaining as it falls?

Elina [12.6K]

<h2>Hello!</h2>

The answer is: B. Kinetic energy

Since the ball is falling, speed increases because the gravity acceleration is acting. When speed increases, the kinetic energy increases too, so the ball is gaining kinetic energy.

The gravity acceleration is equal to $9.81\frac{m}{s^{2}}$ , it means that when falling, the ball will increase it's speed 9.81m every second.

We can calculate the kinetic energy by using the following formula:

$KE=\frac{1}{2}*m*v^{2}$

Where:

$m=mass\\v=velocity$

Have a nice day!

<h2 />

5 0

4 years ago

Which of the following are for vector directione?

Inga [223]

Answer:
C. outside 45 degrees
Step-by-step explanation:
C. outside 45 degrees
because it can be any point or direction outside 45 degrees

8 0

2 years ago

A seesaw is 4.0m long with a pivot at its midpoint. A boy who weighs 400N sits at a distance of 1.5m from the pivot. His sister

bezimeni [28]

Answer:

the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

Explanation:

Given;

length of the seesaw, L = 4.0 m

weight of the boy, W₁ = 400 N

position of the boy from the pivot, d₁ = 1.5 m

weight of her sister, W₂ = 300 N

First, make a sketch of this information given;

0---0.5m---------------------Δ--------------------------4m

↓<--------1.5m-------> <---------x--------->↓

400 N 300N

Apply the principle of moment about the pivot, to determine the value of x;

Sum of anticlockwise moment = sum of clockwise moment

400(1.5) = 300(x)

600 = 300x

x = 600/300

x = 2 cm

Thus, the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

8 0

3 years ago

An electric train moving at 5m/s accelerates to a speed of 8m/s in 20 seconds. Fine the distance travelled in meters during the

adelina 88 [10]

<h3>Answer: 130 meters</h3>

===================================================

Explanation:

vi = 5 and vf = 8 are the initial and final velocities respectively. The change in time is t = 20 seconds.

So,

x = 0.5*(vi + vf)*t

x = 0.5*(5+8)*20

x = 130 meters

represents the distance traveled. The first equation shown above is one of the four kinematics equations.

3 0

3 years ago

Read 2 more answers

The normal force always points ____ to the two surfaces in contact.

shepuryov [24]

Answer:

A..................

6 0

3 years ago