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3 years ago

A man pulls on his dog's leash to keep him from running after a bicycle. Which term best describes this example?

2 answers:

8 0

We know the answer doesn't have to do with force because we have not identified a positive or negative axis.

Depending on what the system we are evaluating is, the sign of the work can change.

If work is done on the system, it is negative, but if work is done by the system, it is positive.

If the system we are evaluating is the leash, the work is being done by the leash, and therefore, the work is positive.

If the system we are evaluating is the dog, the work is being done on the dog, and therefore, the work is negative.

olchik [2.2K]3 years ago

7 0

Answer: so it’s negative work

Explanation:

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5. How much does a 20 m x 10 m x 8 m swimming pool filled with water weigh? Assume that water has a density of 62 kg/m'.

Nookie1986 [14]

Explanation:

First of all we calculate the volume which is 20m×10m×8m= 1600m^3 and then multiply the density by the volume to get the mass which will equal to 99200kg therefore the weight will be

<em><u>Weight</u></em>

mass × acceleration due to gravity

=99200kg × 10m^s^2

=992000N

7 0

3 years ago

Pls help in these 2 questions

Nadya [2.5K]

Answer:

Taking forces along the plane

F cos θ - M g sin θ -100 = M a net of forces along the plane

F = (M a + M g * .5 + 100) / .866 solving for F

F = (80 * 1.5 + 80 * 9.8 * .5 + 100) / .866 = 707 N

F = 707 N acting along the plane

Fn = F sin θ + M g cos θ forces acting perpendicular to plane

Fn = 707 * 1/2 + 80 * 9.8 * .866 = 1030 Newtons forces normal to plane

(this would give a coefficient of friction of 100 / 1030 = .097 = Fn)

4 0

2 years ago

A very long string (linear density 0.7 kg/m ) is stretched with a tension of 70 N . One end of the string oscillates up and down

rewona [7]

To develop this problem it is necessary to apply the concepts related to Wavelength, The relationship between speed, voltage and linear density as well as frequency. By definition the speed as a function of the tension and the linear density is given by

$V = \sqrt{\frac{T}{\rho}}$

Where,

T = Tension

$\rho =$ Linear density

Our data are given by

Tension , T = 70 N

Linear density , $\rho = 0.7 kg/m$

Amplitude , A = 7 cm = 0.07 m

Period , t = 0.35 s

Replacing our values,

$V = \sqrt{\frac{T}{\rho}}$

$V = \sqrt{\frac{70}{0.7}$

$V = 10m/s$

Speed can also be expressed as

$V = \lambda f$

Re-arrange to find \lambda

$\lambda = \frac{V}{f}$

Where,

f = Frequency,

Which is also described in function of the Period as,

$f = \frac{1}{T}$

$f = \frac{1}{0.35}$

$f = 2.86 Hz$

Therefore replacing to find $\lambda$

$\lambda = \frac{10}{2.86}$

$\lambda = 3.49m$

Therefore the wavelength of the waves created in the string is 3.49m

3 0

4 years ago

g A change in the initial _____ of a projectile changes the range and maximum height of the projectile.

docker41 [41]

Answer:

Velocity.

Explanation:

Projectile motion is characterized as the motion that an object undergoes when it is thrown into the air and it is only exposed to acceleration due to gravity.

As per the question, 'any change in the initial velocity of the projectile(object having gravity as the only force) would lead to a change in the range as well as the maximum height of the projectile.' To illustrate numerically:

Horizontal range: As per expression:

R= ( $u^{2}$ *sin2θ)/g