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3 years ago

7

A 142 kg boulder is located near the edge of a cliff 25 m above the ground. What is the gravitational potential energy of the bo

ulder

2 answers:

jarptica [38.1K]3 years ago

8 0

PE = mass * height * 9.81
PE = 142 * 25 * 9.81
PE = 34825.5 J

melisa1 [442]3 years ago

6 0

PE = mass * height * 9.81
PE = 142 * 25 * 9.81
PE = 34825.5 J

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A ball is projected with an initial velocity of 40 meter per second and reached maximum height of 160 meters calculate tge angle

Andru [333]

There's a problem with the question as given. Even with a maximum projection angle of <em>θ</em> = 90°, the initial velocity is not large enough to get the ball up in the air 160 m. With angle 90°, the ball's height <em>y</em> at time <em>t</em> would be

<em>y</em> = (40 m/s) <em>t</em> - 1/2 <em>g t</em> ²

Set <em>y</em> = 160 m, and you'll find that there is no (real) solution for<em> t</em>, so the ball never attains the given maximum height.

From another perspective: recall that

<em>v </em>² - <em>v</em>₀² = 2<em>a </em>∆<em>y</em>

where

• <em>v</em>₀ = initial velocity

• <em>v</em> = final velocity

• <em>a</em> = acceleration

• ∆<em>y</em> = displacement

At its maximum height, the ball has zero vertical velocity, and ∆<em>y</em> = maximum height = 160 m. The ball is in free fall once it's launched, so <em>a</em> = -<em>g</em>.

So we have

0² - (40 m/s)² = -2<em>g </em>(160 m)

but this reduces to

(40 m/s)² = 2 (9.8 m/s²) (160 m)

1600 m²/s² ≠ 3136 m²/s²

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3 years ago

The tendency of an atom to attract electrons towards itself is called

SVEN [57.7K]

Answer:

Electronegativity

Explanation:

Element: <em>An element is a substance which can not be split into simpler units by an ordinary chemical process</em>

Electronegativity: This is the power of an atom in a molecule to attract electrons. The electronegativity of an element increase across the period in the periodic table and decreases down the group. The most electronegative elements are the reactive non metals.

Examples of electronnegative element include, Oxygen, Chlorine, Fluorine, Nitrogen, sulphur etc.

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3 years ago

Three short square wood blocks measuring 3.5 per side support a machine weighing 29500 lbs. What is the compressive stress in th

Ilya [14]

Answer:

D. 803 lbs

Explanation:

In order to find the compressive stress on all three blocks we first need to find the normal surface area of each:

Surface Area of 1 Block = 3.5 x 3.5

Surface Area of 1 Block = 12.25

Surface Area of all 3 Blocks = A = 3 x 12.25

Area = 36.75

Now, the stress is given by the following formula:

Stress = Force/Area

Stress = 29500 lbs/36.75

Stress = 802.72 lbs

Hence, the correct option will be:

<u>D. 803 lbs</u>

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3 years ago

True or False? Mechanical waves do NOT need a medium to travel through.

stellarik [79]

Answer:

False.

Explanation:

Mechanical waves require a medium in order to transport their energy from one location to another.

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2 years ago

Read 2 more answers

What is the orbital velocity in km/s and period in hours of a ring particle at the outer edge of Saturn's A ring

mote1985 [20]

Answer:

The orbital velocity $v = 16.4 \ km/s$

The period is $T = 14.8 \ hours$

Explanation:

Generally centripetal force acting ring particle is equal to the gravitational force between the ring particle and the planet , this is mathematically represented as

$\frac{GM_s * m }{r^2 } = m w^2 r$

=> $w = \sqrt{ \frac{GM}{r^3} }$

Here G is the gravitational constant with value $G = 6.67*10^{-11}$

$M_s$ is the mass of with value $M_s =5.683*10^{26} \ kg$

r is the is distance from the center of the to the outer edge of the A ring

i.e r = R + D

Here R is the radius of the planet with value $R = 60300 \ km$

D is the distance from the equator to the outer edge of the A ring with value $D = 80000 \ kg$

So

$r =80000 + 60300$

=> $r =140300 \ km = 1.4*10^{8} \ m$

So

=> $w = \sqrt{ \frac{ 6.67*10^{-11}* 5.683*10^{26}}{[1.4*10^{8}]^3} }$

=> $w = 1.175*10^{-4} \ rad/s$

Generally the orbital velocity is mathematically represented as

$v = w * r$

=> $v = 1.175*10^{-4} * 1.4*10^{8}$

=> $v = 1.64*10^{4} \ m /s = 16.4 \ km/s$

Generally the period is mathematically represented as

$T = \frac{2 \pi }{w }$

=> $T = \frac{2 * 3.142 }{ 1.175 *10^{-4} }$

=> $T = 53473 \ second = 14.8 \ hours$

Answer:

The orbital velocity $v = 16.4 \ km/s$

The period is $T = 14.8 \ hours$

Explanation:

Generally centripetal force acting ring particle is equal to the gravitational force between the ring particle and the , this is mathematically represented as

$\frac{GM_s * m }{r^2 } = m w^2 r$

3 0

3 years ago