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1 year ago

A footballer kicks a football of mass 430 g and it flies off at a speed of 8 m/s. What is the KE of the football?

Physics

1 answer:

klasskru [66]1 year ago

3 0

Answer:

13.76 Joules

Explanation:

The SI units for joules are defined to be kilogram*meters per second. Therefore, we must turn the grams to kilograms by dividing the answer by 1,000. This is due to 1,000 grams being in a single kilogram. Kinetic energy is defined to be:

$KE=\frac{1}{2} mv^2$

Therefore:

$KE=\frac{1}{2} (0.43kg)(8m/s)^2=13.76J$

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An aquifer pump test was conducted in a confined aquifer where the initial piezometric surface was at elevation 12.45 m, and wel

murzikaleks [220]

Answer:

T = 0.0088 m²/s

Explanation:

given,

initial piezometric elevation = 12.5 m

thickness of aquifer = 14 m

discharge = 28.24 L/s = 0.02824 m³/s

we know

$k = \dfrac{qln(\dfrac{R_2}{R_1})}{2\pi D(H_2-H_1)}$

$k = \dfrac{0.02824 \times ln(\dfrac{75}{25})}{2\pi \times 14 (11.45-10.89)}$

k = 0.629 mm/sec

Transmissibilty

T = k × H

T = 0.629 × 14 × 10⁻³

T = 0.0088 m²/s

4 0

2 years ago

Which property is closely related to its temperature

Lilit [14]

Answer:

Mass – The single most important property that determines other properties of the star. Luminosity – The total amount of energy (light) that a star emits into space. Temperature – surface temperature, closely related to the luminosity and color of the star

Explanation:

8 0

2 years ago

Read 2 more answers

A 600 kg car is at test and then accelerated to 5m/s , what is its original kinetic energy

ycow [4]

Answer:

0 J

Explanation:

Kinetic energy is defined as:

KE = 1/2 m v²

where m is mass and v is velocity.

The car starts at rest, so it has zero velocity. Therefore, its initial kinetic energy is 0 J.

3 0

2 years ago

A 10 kg migratory swan cruises at 20m/s. A calculation that takes into ac-count the necessary forces shows that this motion requ

IgorC [24]

Answer:

Part A:

Distance=864000 m=864 km

Part B:

Energy Used=ΔE=8638000 Joules

Part C:

$\frac{\triangle m}{m}=0.004998=0.49985\%$

Explanation:

Given Data:

v=20m/s

Time =t=12 hours

In Secs:

Time=12*60*60=43200 secs

Solution:

Part A:

Distance = Speed**Time

Distance=v*t

Distance= 20*43200

Distance=864000 m=864 km

Part B:

Energy Used=ΔE= Energy Required-Kinetic Energy of swans

Energy Required to move= Power Required*time

Energy Required to move=200*43200=8640000 Joules

Kinetic Energy= $\frac{1}{2}mv^2$

$K.E\ of\ Swans=\frac{1}{2} *10*(20)^2=2000\ Joules$

Energy Used=ΔE=8640000 -2000

Energy Used=ΔE=8638000 Joules

Part C:

Fraction of Mass used=Δm/m

For This first calculate fraction of energy used:

Fraction of energy=ΔE/Energy required to move

ΔE is calculated in part B

Fraction of energy=8638000/8640000

Fraction of energy=0.99977

Kinetic Energy= $\frac{1}{2}mv^2$

Now, the relation between energies ratio and masses is:

$\frac{\triangle E}{E}=\frac{\triangle m}{2m}v^2$

$\frac{\triangle m}{m}=\frac{2}{v^2} *\frac{\triangle E}{E}\\\frac{\triangle m}{m}=\frac{2}{20^2} *0.99977$

$\frac{\triangle m}{m}=0.004998=0.49985\%$

3 0

3 years ago

Precautions to be taken for the displacement method

finlep [7]

Volume by Displacement. The displacement method (submersion, or dunking method) can be used to accurately measure the volume of the human body and other oddly shaped objects by measuring the volume of fluid displaced when the object is submerged.

The following precautions should be taken very observantly:-

The line of sight must be perpendicular to measuring scale to avoid parallax error. Formation of bubbles inside the cylinder should be completely avoided. Any bubbles within leads to wrong measurements.

8 0

3 years ago