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3 years ago

While rowing in a race, John does 132 J of work while pulling the oar 0.800 m.

Physics

2 answers:

HACTEHA [7]3 years ago

6 0

Answer:

i got u!!! john's arms exert a force of 165 newtons.

Nastasia [14]3 years ago

5 0

Hi there!

$\large\boxed{F = 165 N}$

We know the equation:

W = F · d, where:

W = work (J)

d = displacement (m)

F = force (N)

We can rearrange to solve for F:

W/d = F

Thus:

132/0.8 = F

F = 165 N

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A motorcycle accelerates uniformly from rest and reaches a linear speed of 24.8 m/s in a time of 9.87 s. The radius of each tire

Vinvika [58]

Answer:

8.756 rad/s²

Explanation:

Given that:

A motorcycle accelerates uniformly from rest, then initial velocity v_i = 0 m/s

It final velocity v_f = 24.8 m/s

time (t) = 9.87 s

radius (r) of each tire = 0.287 m

Firstly; the linear acceleration of the motor cycle is determined as follows:

$a_T$ =(V_f - v_i)/t

=(24.8-0)/9.87

=2.513 m/s²

Then; the magnitude of angular acceleration

α = $a_T$ /r

=2.513/0.287

=8.756 rad/s²

6 0

3 years ago

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aev [14]

The bulb

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5 0

4 years ago

A child on a sled is perched at the top of a hill, at a height 7.0 m above the base of the hill. The total mass of the girl plus

spin [16.1K]

Answer:

a)11,71 m/s

b)12.73 m/s

Explanation:

We apply the conservation principle because there is no friction between the hill and the sled:

Total initial energy (Ei) = Total initial energy (Ef), Equation(1)

We define:

K = Kinetic energy = $\frac{1}{2}*m*v^{2}$

U = Potential energy = $m*g*h$

m = mass (kg)

v = velocity (m/s)

h = height (m)

g = gravity acceleration = $9.8m/s^{2}$

A) hi=7m, hf=0 ,vi=0 , vf=?

$Ei=Ef\\Ki+Ui=Kf+Uf$

$1/2*m*vi^{2} +m*g*hi= 1/2*m*vf^{2} +m*g*hf$

$0+m*g*hi=1/2*m*vf^{2}+0$

$(2*m*g*hi)/m=vf^{2}$

$vf=\sqrt{2*g*hi}$

$vf=\sqrt{2*9.8*7}$

$vf=11.71 m/s$

Answer: She reaches the base of the hill with speed of 11.22 m/s

B) hi=7 m, vi=5 m/s, hf=0, vf=?

$m*g*hi+1/2*m*vi^{2} =m*g*hf+1/2*m*vf^{2}$

We divide all terms by m

$g*hi+1/2vi^{2} =g*hf+1/2*vf^{2}$

$9.8*7+1/2*5^{2} =1/2*vf^{2}$

$2(68.6+12.5)=vf^{2}$

$162.2=vf^{2}$

$vf=\sqrt{162.2}$

$vf=12.73 m/s$

Answer: She will move with a speed of 12.73 m/s when she reaches the base of the hill

3 0

3 years ago

A pulley system operates with 40% efficiency. if the work put in is 200 joules, how much useful work is produced?

QveST [7]

1. Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

.40 = useful work / 200

useful work = 80 joules

8 0

4 years ago

Read 2 more answers

How does the principle of electromagnetism explain the interaction between Earth’s magnetic field and the solar wind? I get that

siniylev [52]

Answer:

Explained below.

Explanation:

Electromagnetism is defined as the study of the electromagnetic force that takes place between two or more electrically charged particles.

Now, in electromagnetic interaction, the charged particles tend to interact in an electromagnetic manner through the process of exchanging photons. Therefore, it was concluded from various experiments that the magnetic fields lines of forces were always closed, thereby eliminating the possibility of any magnetic monopole in such a manner that within a particular magnetic field, there will be two poles and in the solar system, the electromagnetic attraction between earth magnetic field and solar wind will be by way of a field.

4 0

3 years ago