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kompoz [17]
2 years ago
10

Find the work done by a weightlifter lifting a 20kg barbell 2.2 m upward at a constant speed.

Physics
1 answer:
mario62 [17]2 years ago
3 0

Answer:

440J

Explanation:

First, let us find the <u>weight </u>of the barbell.

The formula to find the weight is :

W = m × g

Here,

m ⇒ mass ⇒ 20 kg

g ⇒ acceleration of gravity

<u>Let us find it now.</u>

W = m × g

W = 20 kg × 10 ms⁻²

W = 200N

And now let us find<u> the work done by this weight lifter.</u>

Work = Force × Displacement

<u>Let us find it now.</u>

Work = Force × Displacement

         = 200N × 2.2m

         =<u> 440J</u>

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Which of the following statements about the nature of electrical charge is FALSE? Positive-positive or negative-negative charges
Ilya [14]

Answer:

All of the above statements are true.

Explanation:

All matter is composed of atoms of which have subatomic particles. Subatomic particles are electrons, protons and neutrons. Each particle has electric charges.

Electrons have a negative charge, protons have a positive charge and neutrons have zero charge.

Between two nearby charges initially at rest, a type of forces, called electrostatic, is always established in such a way that, if the charged particles are small enough so that they can be considered punctual, the following conditions are met:

  • The force established between the two has a direction that coincides with an imaginary straight line that joins the two charges.
  • The force exerted on one load points towards the other when the two have different signs, one positive and the other negative. (attractive force).
  • The sense of force is directed to the opposite side of the charge when both have the same sign (repulsive force).
4 0
4 years ago
A 0.2-stone is attached to a string and swung in a circle of radius 0.6 m on a horizontal and frictionless surface. If the stone
Nikitich [7]

Answer:

2960 N

Explanation:

Convert rev/min to rad/s:

150 rev/min × (2π rad/rev) × (1 min / 60 s) = 50π rad/s

Sum of forces in the centripetal direction:

∑F = ma

T = m v² / r

T = m ω² r

T = (0.2 kg) (50π rad/s)² (0.6 m)

T = 2960 N

3 0
3 years ago
Calculate the size of the labor force. The size of the adult population is 30,000. The number working is 17,700 and the number o
allsm [11]

Answer:

The size of the labor force is 19300.

Explanation:

Given that,

Adult population = 30000

Number of  employed = 17700

Number of unemployed = 1600

Suppose, The labor force is comprised of those who are working for any number of hours (the employed) and those who are out of work but actively looking for a job the unemployed)

We need to calculate the size of the labor force

The labor force is comprised of number of employed person and number of unemployed person.

That means,

Labor Force = Employed + Unemployed

F_{l}=17700+1600

F_{l}=19300

Hence, The size of the labor force is 19300.

4 0
3 years ago
Read 2 more answers
Someone please help<br> Just need answers
marishachu [46]

Answer:

As follows,

Explanation:

KE=1/2mv^2

In 1st question,

KE=1/2mv^2=1/2*0.05*12=0.3 J [50g=0.05 kg]

In 2nd question,

KE=1/2mv^2

6.8=1/2*0.046*v^2

v=sqrt(6.8/0.023)

v=17.19

In 3rd question,

KE=1/2mv^2

63/392=m

m=0.16kg=160g

For 4th,

a.

1st case,

KE=1/2mv^2=1/2*28*2.4^2=80.64

2nd case,

KE=1/2mv^2=1/2*28*3.7^2=191.66

Change in KE=191.66-80.64=11.02

b.Speed/velocity gained

6 0
3 years ago
Please hurry please
Ghella [55]

Answer:

0.765m

Explanation:

gravitational potential energy GPE = mass * acceleration due to gravity * height

Given

GPE = 30Joules

Mass m = 4kg

acceleration = 9.8m/s²

Required

Height h

From the formula

h = GPE/mg

h = 30/4(9.8)

h = 30/39.2

h = 0.765m\

Hence the height of the counter is 0.765m

4 0
3 years ago
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