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3 years ago

A man has 887.5 J of kinetic energy while running with a velocity of 5 m/s. What is his mass?

Physics

1 answer:

monitta3 years ago

7 0

Answer:

The mass of the man is 71 kg

Explanation:

Given;

kinetic energy of the man, K.E = 887.5 J

velocity of the man, v = 5 m/s

The mass of the man is calculated as follows;

K.E = ¹/₂mv²

where;

m is the mass of the man

2K.E = mv²

m = 2K.E / v²

m = (2 x 887.5) / (5)²

m = 71 kg

Therefore, the mass of the man is 71 kg

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A man is traveling on a bicycle at 14 m/s along a straight road that runs parallel to some railroad tracks. He hears the whistle

deff fn [24]

Answer:

Explanation:

b ) The problem is based on Doppler's effect of sound

f = f₀ x (V - v₀) /( $V+v_s$ )

f is apparent frequency ,f₀ is real frequency , V is velocity of sound , v₀ is velocity of observer going away , $v_s$ is velocity of source going away

778 = 840 x (340 - 14)/ (340 + $v_s$ )

340 + $v_s$ = 341.18

$v_s$ = 1.18 m /s

it will go away from the observer or the cyclist.

speed of train = 1.18 m /s

a )

For a stationary observer v₀ = 0

f = f₀ x V /( $V+v_s$ )

= 840 x 340 / (340 + 1.180)

= 837 Hz

6 0

3 years ago

Un cuerpo se lanza verticalmente hacia arriba con una velocidad de 13 m/s. ¿Cuánto tiempo tarda en alcanzar la altura máxima? a)

Elena L [17]

Answer:

D. 1.33 segundos.

Explanation:

El cuerpo es experimenta un movimiento en caída libre al modificarse su velocidad por efecto de la gravitación terrestre. Este cuerpo alcanza instantáneamente el reposo cuando se encuentra a su altura máxima, el tiempo puede obtenerse sabiendo la aceleración y las velocidades incial y final a partir de la siguiente ecuación cinemática:

$v = v_{o}+g\cdot t$

Donde:

$v$ - Velocidad final del cuerpo, medida en metros por segundo.

$v_{o}$ - Velocidad inicial del cuerpo, medida en metros por segundo.

$g$ - Aceleración gravitacional, medida en metros por segundo al cuadrado.

$t$ - Tiempo, medido en segundos.

Ahora se despeja el tiempo:

$t = \frac{v-v_{o}}{g}$

Si $v_{o} = 13\,\frac{m}{s}$ , $v=0\,\frac{m}{s}$ y $g = -9.807\,\frac{m}{s^{2}}$ , entonces:

$t = \frac{0\,\frac{m}{s}-13\,\frac{m}{s}}{-9.807\,\frac{m}{s^{2}} }$

$t = 1.326\,s$

Por ende, la respuesta correcta es D.

6 0

3 years ago

What is your worldview? Explain?

zimovet [89]

My worldview is someone who doesn't exist. Someone who isn't real but i want them to BE real. It's not possible to have someone who is alike you. Who is there for yo when you need them

5 0

3 years ago

A 125-kg merry-go-round in the shape of a uniform, solid, horizontal disk of radius 1.50 m is set in motion by wrapping a rope a

lbvjy [14]

Answer:

201.6 N

Explanation:

m = mass of disk shaped merry-go-round = 125 kg

r = radius of the disk = 1.50 m

w₀ = Initial angular speed = 0 rad/s

w = final angular speed = 0.700 rev/s = (0.700) (2π) rad/s = 4.296 rad/s

t = time interval = 2 s

α = Angular acceleration

Using the equation

w = w₀ + α t

4.296 = 0 + 2α

α = 2.15 rad/s²

I = moment of inertia of merry-go-round

Moment of inertia of merry-go-round is given as

I = (0.5) m r² = (0.5) (125) (1.50)² = 140.625 kgm²

F = constant force applied

Torque equation for the merry-go-round is given as

r F = I α

(1.50) F = (140.625) (2.15)

F = 201.6 N

4 0

3 years ago

A string with a length of 4.00 m is held under a constant tension. The string has a linear mass density of \mu=0.000600~\text{kg

yulyashka [42]

Answer:

$T=245.76N$

Explanation:

We know that the frequency of the nth harmonic is given by $f_n=nf$ , where $f$ is the fundamental harmonic. Since we have the values of two consecutive frequencies, we can do: