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3 years ago

How can a karate expert break a concrete block

Physics

1 answer:

FinnZ [79.3K]3 years ago

8 0

Many ways, but some of the most famous are kicks (side, back, front, snap) or a smash.

Hope it helped! :)

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plsssssss i need help Which source of law is most like common law: statutes, case law, or administrative law? Explain

Lisa [10]

Answer:

The answer is "case law".

Explanation:

This law is not based on law, but on legislatures, statutes, or legislation, on judgments. Its also used as a different term with common law, which is the collection of precedents as well as power on a specific subject established in previous judicial decisions that are a part of Common law, which is also recognized as case law to establish by the court system based on legal case law.

7 0

3 years ago

A disk with radius R and uniform positive charge density s lies horizontally on a tabletop. A small plastic sphere with mass M a

Yanka [14]

Answer:

a. F = Qs/2ε₀[1 - z/√(z² + R²)] b. h = (1 - 2mgε₀/Qs)R/√[1 - (1 - 2mgε₀/Qs)²]

Explanation:

a. What is the magnitude of the net upward force on the sphere as a function of the height z above the disk?

The electric field due to a charged disk with surface charge density s and radius R at a distance z above the center of the disk is given by

E = s/2ε₀[1 - z/√(z² + R²)]

So, the net force on the small plastic sphere of mass M and charge Q is

F = QE

F = Qs/2ε₀[1 - z/√(z² + R²)]

b. At what height h does the sphere hover?

The sphere hovers at height z = h when the electric force equals the weight of the sphere.

So, F = mg

Qs/2ε₀[1 - z/√(z² + R²)] = mg

when z = h, we have

Qs/2ε₀[1 - h/√(h² + R²)] = mg

[1 - h/√(h² + R²)] = 2mgε₀/Qs

h/√(h² + R²) = 1 - 2mgε₀/Qs

squaring both sides, we have

[h/√(h² + R²)]² = (1 - 2mgε₀/Qs)²

h²/(h² + R²) = (1 - 2mgε₀/Qs)²

cross-multiplying, we have

h² = (1 - 2mgε₀/Qs)²(h² + R²)

expanding the bracket, we have

h² = (1 - 2mgε₀/Qs)²h² + (1 - 2mgε₀/Qs)²R²

collecting like terms, we have

h² - (1 - 2mgε₀/Qs)²h² = (1 - 2mgε₀/Qs)²R²

Factorizing, we have

[1 - (1 - 2mgε₀/Qs)²]h² = (1 - 2mgε₀/Qs)²R²

So, h² = (1 - 2mgε₀/Qs)²R²/[1 - (1 - 2mgε₀/Qs)²]

taking square-root of both sides, we have

√h² = √[(1 - 2mgε₀/Qs)²R²/[1 - (1 - 2mgε₀/Qs)²]]

h = (1 - 2mgε₀/Qs)R/√[1 - (1 - 2mgε₀/Qs)²]

4 0

2 years ago

What is the static friction force??

Paul [167]

55 Kg has a weight of 55x9.8= 539 N
That is equal to the Normal force.
The static friction = 0.19 x 539 = 102.4 N

6 0

3 years ago

What is the velocity in meters per second of a runner who runs exactly 110 m toward the beach in 72 seconds.

KATRIN_1 [288]

1.53 m/s toward the beach

Explanation:

The magnitude of the velocity of the runner is given by:

$v=\frac{d}{t}$

where

d is the displacement of the runner

t is the time taken

In this case, d=110 m and t=72 s, so the velocity of the runner is

$v=\frac{110 m}{72 s}=1.53 m/s$

Velocity is a vector, so it consists of both magnitude and direction: we already calculate the magnitude, while the direction is given by the problem, toward the beach.

3 0

3 years ago

Read 2 more answers

A cheetah can accelerate from rest to a speed of 21.5 m/s in 6.75 s. What is its acceleration? m/s^2

grandymaker [24]

Answer:

Acceleration will be $a=3.185m/sec^2$