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borishaifa [10]
4 years ago
8

A 30-kg child sits at the top of a 3-meter slide. After sliding down, the child is traveling 4 m/s. How much PE does he start wi

th? How much KE does he end with? How much energy is lost to friction?
Physics
1 answer:
Jobisdone [24]4 years ago
6 0
At the top:

         Potential Energy = (mass) x (gravity) x (height)

                                       = (30 kg) x (9.8 m/s²) x (3 meters)

                                       =      882 joules

At the bottom:

           Kinetic Energy  =  (1/2) x (mass) x (speed)²

                                       = (1/2) x (30 kg) x (3 m/s)²

                                       =        (15 kg)  x  (9 m²/s²)

                                       =              135 joules .

He had  882 joules of potential energy at the top,
but only  135 joules of kinetic energy at the bottom.

Friction stole  (882 - 135) = 747 joules of his energy while he slid down.
The seat of his jeans must be pretty warm.
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Nana76 [90]

Answer:

λ = 5.656 x 10⁻⁷ m = 565.6 nm

Explanation:

Using the formula of fringe spacing from the Young's Double Slit experiment, which is given as follows:

\Delta x = \frac{\lambda L}{d}\\\\\lambda = \frac{\Delta x\ d}{L}

where,

λ = wavelength = ?

Δx = fringe spacing = 1.6 cm = 0.016 m

L = Distance between slits and screen = 4.95 m

d = slit separation = 0.175 mm = 0.000175 m

Therefore,

\lambda = \frac{(0.016\ m)(0.000175\ m)}{4.95\ m}\\\\

<u>λ = 5.656 x 10⁻⁷ m = 565.6 nm</u>

6 0
3 years ago
Which of the following is NOT an argument for showing that the Earth must be round: a. during an eclipse of the Moon, the shadow
Hitman42 [59]

Answer: The correct option is option E (the Sun is seen blocking different constellations in the course of a year.

Explanation:

The earth, which is one of the planets of the solar system that supports life, is shperical in shape. The spherical ( round) shape of the earth is marked by the intervening highlands and oceans on its surface.

Evidence to show that the earth is shperical are:

--> The Lunar eclipse: During an eclipse of the Moon, the shadow of the Earth is always seen to be round.

--> Ships Visibility: When ships travel a large distance away, we see their hulls disappear first and their masts disappear last.

-->Altitude of Polaris (North Star): The height of the North Star changes as we travel to different latitudes. That is ,increases as you move toward the North pole, or decreases as you move toward the equator.

--> Aerial photographs: Photographs of the Earth from space always show a round body.

The statement that doesn't prove that the earth is spherical in shape is (the Sun is seen blocking different constellations in the course of a year). The sun is seen in front of stars blocking different constellation in a year because the earth orbits round the sun in a year and not that it is shperical in shape.

4 0
3 years ago
Is this a plant or animal cell????
Lubov Fominskaja [6]
This is an Animal Cell.
4 0
4 years ago
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It is rate for any motion to
Gnoma [55]

Answer:

a. stay the same for very long

Explanation:

It is rare for any motion to stay the same for a very long time. The force applied on a body causes changes in the magnitude of motion.

  • For motion to remain constant, there must not be a net force acting on the body
  • All the forces on the body must be balanced.
  • This is very hard to come by.
  • Motion changes very frequently.
3 0
3 years ago
In a tug-of-war game on one campus, 15 students pull on a rope at both ends in an effort to displace the central knot to one sid
mojhsa [17]

Answer:

Net pull = 110 N to the left

Explanation:

Group the different pulls according to the direction (right or left)

2 pull 196 N each to the right

4 pull 98 N each to the left

5 pull 62 N each to the left

3 pull 150 N each to the right

1 pull 250 N to the left

Since positive direction is to the right, the pulls to the left will have a minus (-)

Net Force= 2(196)+4(-98)+5(-62)+3(150)+1(-250) \\Net Force = -110

The resulting force is negative, meaning the direction is to the left

6 0
3 years ago
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