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wlad13 [49]
3 years ago
8

A pear hangs in a tree at a height of 1.8 m. The pear has a mass of 0.2 kg. The pear falls out of the tree and lands on the grou

nd. (Use correct units in all answers.)
a. How much gravitational potential energy does the pear have before it falls?

b. How much kinetic energy does the pear have when it reaches the ground?

c. How fast is the pear moving when it hits the ground?
Physics
1 answer:
TiliK225 [7]3 years ago
6 0

a) PE=mgh=0.2*9.8*1.2=2.352 J

b) KE=PE=2.352 J

c) v=\sqrt{\frac{2KE}{m}}=4.85 m/s

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A mass is attached to a spring with an unknown spring constant. The spring gains 10 J of elastic potential energy if stretched b
Firlakuza [10]

From the given information in the question, the correct option is Option 1: 14 cm.

A non-stretched elastic spring has a conserved potential energy which gives it the ability to perform work. The elastic potential energy can be expressed as:

PE = \frac{1}{2} k x^{2}

Where PE is the energy, k is the spring constant and x is extension.

i. Given that: PE = 10 J and x = 10 cm, then;

PE = \frac{1}{2} k x^{2}

10 = \frac{1}{2} k 10^{2}

20 = 100k

k = 0.2 J/cm

ii. To determine how far the spring is needed to be stretched, given that PE = 20 J.

PE = \frac{1}{2} k x^{2}

20 = \frac{1}{2} (0.2) x^{2}

40 = 0.2 x^{2}

x^{2} = 200

x = \sqrt{200}

  = 14.1421

x = 14.14 cm

So that;

x is approximately 14.00 cm.

Thus, the spring need to be stretched to 14.00 cm to give the spring 20 J of elastic potential energy.

For more information, check at: brainly.com/question/1352053.

8 0
3 years ago
An electron is initially moving at 1.4 x 107 m/s. It moves 3.5 m in the direction of a uniform electric field of magnitude 120 N
algol13

Answer:

K.E = 15.57 x 10⁻¹⁷ J

Explanation:

First, we find the acceleration of the electron by using the formula of electric field:

E = F/q

F = Eq

but, from Newton's 2nd Law:

F = ma

Comparing both equations, we get:

ma = Eq

a = Eq/m

where,

E = electric field intensity = 120 N/C

q = charge of electron = 1.6 x 10⁻¹⁹ C

m = Mass of electron = 9.1 x 10⁻³¹ kg

Therefore,

a = (120 N/C)(1.6 x 10⁻¹⁹ C)/(9.1 x 10⁻³¹ kg)

a = 2.11 x 10¹³ m/s²

Now, we need to find the final velocity of the electron. Using 3rd equation of motion:

2as = Vf² - Vi²

where,

Vf = Final Velocity = ?

Vi = Initial Velocity = 1.4 x 10⁷ m/s

s = distance = 3.5 m

Therefore,

(2)(2.11 x 10¹³ m/s²)(3.5 m) = Vf² - (1.4 x 10⁷)²

Vf = √(1.477 x 10¹⁴ m²/s² + 1.96 x 10¹⁴ m²/s²)

Vf = 1.85 x 10⁷ m/s

Now, we find the kinetic energy of electron at the end of the motion:

K.E = (0.5)(m)(Vf)²

K.E = (0.5)(9.1 x 10⁻³¹ kg)(1.85 x 10⁷ m/s)²

<u>K.E = 15.57 x 10⁻¹⁷ J</u>

4 0
3 years ago
I'm writing a story about Granny using old-fashioned laundry bluing to freshen dingy yellow clothes. I would like to explain WHY
Katena32 [7]

By combining blue with yellow light is like combining blue light with red and green light. The result of combining these three primary colors of light is to produce white light.

<h3>What is laundry bluing ?</h3>

Laundry bluing is a product adds a trace amount of blue dye to white fabric during laundering to improve its appearance.

Bluing products in higher concentrations can darken jeans and other blue cloth.

The blue overpowered the yellow to reflect white (at least the appearance of white to the human eye).

Blue and yellow are complementary colors that combine to reflect white, Fabrics.

Here,

Yellow light is a combination of red and green light. So combining blue with yellow light is like combining blue light with red and green light. The result of combining these three primary colors of light is to produce white light.

Learn more about White light here:brainly.com/question/16317768

#SPJ1

7 0
2 years ago
Two astronauts in space with a baseball decide to play catch to pass the time. In the language of conservation of momentum, desc
Anna35 [415]
As the first astronaut throws the ball, lets assume it goes with v velocity and the mass of the ball be m
the momentum comes out be mv, thus to conserve that momentum the astronaut will move opposite to the direction of the ball's motion with the velocity mv/M (where M is the mass of the astronaut).
4 0
3 years ago
Read 2 more answers
HELP DUE TODAY BEST ANSWER GET BRAINLIE
Aleonysh [2.5K]

I uploaded the answer to a file hosting. Here's link:

tinyurl.com/wpazsebu

3 0
3 years ago
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