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defon
3 years ago
13

Is work being done on a barbell when a weight lifter is holding the barbell over his head?

Physics
1 answer:
Artemon [7]3 years ago
5 0

Answer:

Because in order for work to be done on an object, the object must be moving. Why isn't work being done on a barbell when a weight lifter is holding the barbell over his head? Work is maximized when force is applied in the same direction that the object is moving. ... In order to do work faster, more_is required.

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A ruler has a division of 1mm. You use the ruler to measure a piece of paper. You find that it is 7.4 cm wide and 8.3 cm long. W
Anastaziya [24]

Answer:

<h2><em>6,142mm²</em></h2>

Explanation:

Given the dimension of a paper measured by a ruler as 7.4 cm wide and 8.3 cm long, the area of the paper is expressed using the area for calculating the area of a rectangle as shown;

Area of the piece of paper = Length * Width

Given length = 7.4cm

Length = 74mm (Since 10mm = 1cm)

Width = 8.3cm

Width (in mm) = 83mm

We converted to mm since the ruler used to measure has a division of 1mm.

Substituting the given values into the formula, we will have:

Area of the piece of paper = 74mm * 83mm

Area of the piece of paper = 6,142mm²

<em>Hence, the area of the piece of paper is 6,142mm²</em>

3 0
2 years ago
An 800 kHz radio signal is detected at a point 3.2 km distant from a transmitter tower. The electric field amplitude of the sign
hammer [34]

Answer:

1.07 nT

Explanation:

We know that E/B = c where E = electric field amplitude = 320 mV/m = 0.32 V/m, B = magnetic field amplitude and c = speed of light = 3 × 10⁸ m/s.

So, B = E/c

Substituting E and c into B, we have

B = E/c

= 0.32 V/m ÷ 3 × 10⁸ m/s

= 0.1067 × 10⁻⁸ T

= 1.067 × 10⁻⁹ T

= 1.067 nT

≅ 1.07 nT

3 0
3 years ago
You accidentally slide a glass of iced tea off a table that is 0.75 m tall. How
Marizza181 [45]

Answer:

B

Explanation:

s=  \frac{1}{2} gt ^{2}

s=0.75

g=10

3 0
3 years ago
Read 2 more answers
A 12.0-g bullet is fired horizontally into a 109-g wooden block that is initially at rest on a frictionless horizontal surface a
kykrilka [37]

Answer:

v₀ = 280.6 m / s

Explanation:

we have the shock between the bullet and the block that we can work with at the moment and another part where the assembly (bullet + block) compresses a spring, which we can work with mechanical energy,

We write the mechanical energy when the shock has passed the bodies

   Em₀ = K = ½ (m + M) v²

We write the mechanical energy when the spring is in maximum compression

Em_{f} = K_{e} \\= \frac{1}{2} kx^2\\    Em_0 = Em_{f}

½ (m + M) v² = ½ k x²

Let's calculate the system speed

   v = √ [k x² / (m + M)]

   v = √[152 ×0.78² / (0.012 +0.109) ]

   v = 27.65 m / s

This is the speed of the bullet + Block system

Now let's use the moment to solve the shock

Before the crash

   p₀ = m v₀

After the crash

p_{f} = (m + M) v

The system is formed by the bullet and block assembly, so the forces during the crash are internal and the moment is preserved

 p_0 =  p_{f}

  m v₀ = (m + M) v

  v₀ = v (m + M) / m

let's calculate

v₀ = 27.83 (0.012 +0.109) /0.012

  v₀ = 280.6 m / s

4 0
2 years ago
Which part of the brain serves to regulate the endocrine system?
Debora [2.8K]

Answer:

hypothalamus

Explanation:

The hypothalamus is known as the master switchboard because it's the part of the brain that controls the endocrine system. The pituitary gland, which hangs by a thin stalk from the hypothalamus, is called the master gland of the body because it regulates the activity of the endocrine glands.

7 0
3 years ago
Read 2 more answers
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