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2 years ago

Why doesn't a ball roll on forever after being kicked at a soccer game?

Physics

2 answers:

borishaifa [10]2 years ago

7 0

Friction of the grass and gravity holding it down

Naddika [18.5K]2 years ago

6 0

Because of gravity and friction.

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as your roller coaster climbs to the top of the steepest hill on its track when does the first car have the greatest potential e

pochemuha

...the potential energy that you build while going up the hill on the roller coaster could be let go as kinetic energy -- the energy of motion that takes you down the hill of the roller coaster.

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2 years ago

When Anna eats an apple, the sugars in that apple are broken down into the substance called glucose. Glucose is then burned in h

Alex777 [14]

Answer:

Chemical energy is converted to thermal energy and electrical energy.

Explanation:

The sugar present in the apple is broken down into Glucose. This is chemical energy stored in the apple which is broken down into energy which is utilized by body for everyday works. The chemical energy gets converted to thermal energy which warms the body and electrical energy due to which the heart beats.

7 0

2 years ago

Read 2 more answers

If Pete ( mass=90.0kg) weights himself and finds that he weighs 30.0 pounds, how far away from the surface of the earth is he

shutvik [7]

Answer: 9938.8 km

Explanation:

1 pound-force = 4.48 N

30.0 pounds-force = 134.4 N

The force of gravitation between Earth and object on the surface of is given by:

$F = \frac{GMm}{R^2} = mg$

Where M is the mass of the Earth, m is the mass of the object, R (6371 km) is the radius of the Earth.

At height, h above the surface of the Earth, the weight of the object:

$(mg)'= \frac{GMm}{(R+h)^2}$

we need to find "h"

taking the ratio of two:

$\frac{mg}{(mg)'}=\frac{(R+h)^2}{R^2}\\ \Rightarrow \frac{90kg \times 9.8 m/s^2}{134.4 N}=\frac{(R+h)^2}{R^2}\\ \Rightarrow 6.56 R^2= (R+h)^2 \Rightarrow h= (2.56-1)R\\ \Rightarrow h = 1.56 R = 1.56 \times 6371 km = 9938. 8 km$

Hence, Pete would weigh 30 pounds at 9938.8 km above the surface of the Earth.

5 0

2 years ago

An observer O is standing on a platform of length L = 90 m on a station. A rocket train passes at a relative (constant) speed of

Natali [406]

Answer:

Explanation:

Since the front and back of the rocket simultaneously line up with forward and backward end of the platform respectively .

Then length of the platform = length of the train rocket .

A )

Time to cross a particular point on the platform

= length of rocket train / .96 x 3 x 10⁸

= 90 / .96 x 3 x 10⁸

= 31.25 x 10⁻⁸ s

B) Rest length of the rocket = length of platform = 90 m

C ) length of platform as viewed by moving observer =

$\frac{90}{\sqrt{1-\frac{v^2}{c^2 } } }$

= $\frac{90}{\sqrt{1-\frac{0.92}{1 } } }$

= 321 m

D ) For the observer on platform time taken = 31.25 x 10⁻⁸ s

for the observer in the rocket , time will be dilated so time recorded by observer in motion ,

$31.25\times10^{-8} \times \sqrt{1-\frac{.96^2}{1} }$

8.75 x 10⁻⁸ s .

8 0

2 years ago

You are using a rope to lift a 14.5 kg crate of fruit. Initially you are lifting the crate at 0.500 m/s. You then increase the t

lina2011 [118]

Answer:

W = 172.5 J

Explanation:

given,

mass of the fruit crate = 14.5 kg

initial velocity to lift = 0.500 m/s

increase in the tension = 150 N

lift of crate = 1.15 m

work done by the tension = ?

work done = force x displacement

W = F s cos θ

θ = 0°

W = F s x cos 0

W = 150 x 1.15 x 1

W = 172.5 J

Work done on the crate by the tension force = W = 172.5 J

5 0

2 years ago