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3 years ago

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A 50. g pendulum swinging back and forth has a speed of 3.0 m/s at a height of 0.30 m. Determine the total mechanical energy of

the pendulum.
370 J
220 J
0.22 J
0.37 J

2 answers:

mr Goodwill [35]3 years ago

7 0

Answer:

it is .37 J

Explanation:

Lena [83]3 years ago

4 0

The answer is D 0.37 J
convert 50 g to kg and you get .05 kg
the total mechanical energy is kinetic energy plus the potential energy.
so Etotal=1/2mv^2+mgh
Etotal=1/2*(.05kg)*(3.0m/s)^2+(.05kg)*(9.8m/s^2)*(0.30m)
Etotal=0.37 J

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A 2.0 kg block on a horizontal frictionless surface is attached to a spring whose force constant is 590 N/m. The block is pulled

SVETLANKA909090 [29]

Answer:

The value is $v = -0.04 \ m/s$

Explanation:

From the question we are told that

The mass of the block is $m = 2.0 \ kg$

The force constant of the spring is $k = 590 \ N/m$

The amplitude is $A = + 0.080$

The time consider is $t = 0.10 \ s$

Generally the angular velocity of this block is mathematically represented as

$w = \sqrt{\frac{k}{m} }$

=> $w = \sqrt{\frac{590}{2} }$

=> $w = 17.18 \ rad/s$

Given that the block undergoes simple harmonic motion the velocity is mathematically represented as

$v = -A w sin (w* t )$

=> $v = -0.080 * 17.18 sin (17.18* 0.10 )$

=> $v = -0.04 \ m/s$

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4 years ago

An average person can reach a maximum height of about 60 cm when jumping straight up from a crouched position. During the jump i

Iteru [2.4K]

Answer:

Explanation:

Height attained by body = 50 cm

= .5 m

Initial velocity = u

v² = u² - 2gh

0 = u² - 2gh

u² = 2 x 9.8 x .5

u = 3.13 m /s

During the initial period , the muscle stretches by around 10 cm during which force by ground reacts on the body and gives acceleration to achieve velocity of 3.13 m/s from zero .

v² = u² + 2as

3.13² = 0 + 2 a x .10

a = 49 m/s²

reaction by ground R

Net force

R-mg = ma

R= m ( g +a )

= mg + ma

=W + (W/g) x a

W ( 1 + a / g )

= W ( 1 + 49 / 9.8 )

= 6W

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4 years ago

1. if the work done to move a box to a distance of 6 metres equals 120 joules. calculate the force

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Explanation:

1. W = F x D

F = W/D

F = 120/6 = 20Newton

2. P. E = mgh

P. E = 1.5x10x2 = 30Joules

3. It means that the energy the body possesses at that point is 20Joules

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3 years ago

What is the frequency of a wave with a speed of 45 m/s and a wavelength of 2.5 m

mart [117]

Answer:

.05

Explanation:

wavelength/frequency = wave speed

45 = 2.5/x

x = 0.05

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3 years ago

A tank, shaped like a cone has height 12 meter and base radius 1 meter. It is placed so that the circular part is upward. It is

Temka [501]

Answer:

376966.991 Joules

Explanation:

Given that :

the height = 12 m

Let assume the tank have a thickness = dh

The radius of the tank by using the concept of similar triangle is :

$\dfrac{1}{r} = \dfrac{12}{h}$

$r = \dfrac{h}{12}$

The area of the tank = $\mathbf{\pi r^2}$

The area of the tank = $\mathbf{\pi( \dfrac{h}{12})^2}$

The area of the tank = $\mathbf{ \dfrac{\pi}{144}h^2}$

The volume of the tank is = area × thickness

= $\mathbf{ \dfrac{\pi}{144}h^2 \ dh}$

Weight of the element = $\rho_ g * volume$

where;

$\rho_g$ = density of water ; which is given as 10000 N/m³

So;

Weight of the element = $\mathbf{ 10000 *\dfrac{\pi}{144}h^2 \ dh}$

Weight of the element = $\mathbf{69.44 \ \pi \ h^2 \ dh}$

However; the work required to pump this water = weight × height rise

where the height rise = 12 - h

the work required to pump this water = $\mathbf{69.44 \ \pi \ h^2 \ dh}$ (12 - h)

the work required to pump this water = $\mathbf{69.44 \pi (12h^2-h^3)dh}$

We can determine the total workdone by integrating the work required to pump this water

SO;

Workdone = $\mathbf{\int\limits^{12}_0 {69.44 \pi(12h^2-h^3)} dh}$

= $\mathbf{ 69.44 \pi \int\limits^{12}_0 {(12h^2-h^3)} dh}$

= $\mathbf{ 69.44 \pi[ \frac{12h^3}{3}- \frac{h^4}{4}]^{12}}_0} }$

= $\mathbf{69.44 \pi [ \frac{12^4}{3}-\frac{12^4}{4}]}$

= $\mathbf{69.44 \pi*12^4 [ \frac{4-3}{12}]}$

= $\mathbf{69.44 \pi*12^4 *\frac{1}{12}}$

= 376966.991 Joules

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3 years ago