Si se suelta una moneda desde lo alto de una casa, su velocidad inicial es <br> 4 puntos

In a Broadway performance, an 77.0-kg actor swings from a R = 3.65-m-long cable that is horizontal when he starts. At the bottom

krek1111 [17]

Answer: h =1.22 m

Explanation:

from the question we were given the following

mass of performer ( M1 ) = 77 kg

length of cable ( R ) = 3.65 m

mass of costar ( M2 ) = 55 kg

maximum height (h) = ?

acceleration due to gravity (g) = 9.8 m/s^2 (constant value)

We first have to find the velocity of the performer. From the work energy theorem work done = change in kinetic energy

work done = 1/2 x mass x ( (final velocity)^2 - (initial velocity)^2 )

initial velocity is zero in this case because the performer was at rest before swinging, therefore

work done = 1/2 x 77 x ( v^2 - 0)

work done = 38.5 x ( v^2 ) ......equation 1

work done is also equal to m x g x distance ( the distance in this case is the length of the rope), hence equating the two equations we have

m x g x R = 38.5 x ( v^2 )

77 x 9.8 x 3.65 = 38.5 x ( v^2 )

2754.29 = 38.5 x ( v^2 )

( v^2 ) = 71.54

v = 8.4 m/s ( velocity of the performer)

After swinging, the performer picks up his costar and they move together, therefore we can apply the conservation of momentum formula which is

initial momentum of performer (P1) + initial momentum of costar (P2) = final momentum of costar and performer after pick up (Pf)

momentum = mass x velocity therefore the equation above now becomes

(77 x 8.4) + (55 x 0) = (77 +55) x Vf

take note the the initial velocity of the costar is 0 before pick up because he is at rest

651.3 = 132 x Vf

Vf = 4.9 m/s

the performer and his costar is 4.9 m/s after pickup

to finally get their height we can use the energy conservation equation for from after pickup to their maximum height. Take note that their velocity at maximum height is 0

initial Kinetic energy + Initial potential energy = Final potential energy + Final Kinetic energy

where

kinetic energy = 1/2 x m x v^2

potential energy = m x g x h

after pickup they both will have kinetic energy and no potential energy, while at maximum height they will have potential energy and no kinetic energy. Therefore the equation now becomes

initial kinetic energy = final potential energy

(1/2 x (55 + 77) x 4.9^2) + 0 = ( (55 + 77) x 9.8 x h) + 0

1584.7 = 1293 x h

h =1.22 m

3 0

3 years ago

Unseen objects in our galaxy have been found by the bending effect they have on more distant stars' light passing near them. The

Dimas [21]

Answer:

a

Explanation:

5 0

3 years ago

An object's true weight is 123 N. When it is completely submerged in water, its

SashulF [63]

Object true weight is given as

$mg = 123 N$

now we know that g = 9.8 m/s^2

$m* 9.8 = 123$

$m = \frac{123}{9.8} = 12.55 kg$

now when it is complete submerged in water its apparent weight is given as 82 N

apparent weight = weight - buoyancy force

apparent weight = 82 N

weight = 123 N

now we have

82 = 123 - buoyancy force

buoyancy force = 123 - 82 = 41 N

now we also know that buoyancy force is given as

$F_b = p_{liq}Vg$

$41 = 1000*V*9.8$

$V = \frac{41}{1000*9.8}$

$V = 4.18 * 10^{-3} m^3$

now as we know that mass of the object is 12.55 kg

its volume is 4.18 * 10^-3 m^3

now we know that density will be given as mass per unit volume

$density = \frac{m}{V}$

$density = \frac{12.55}{4.18*10^{-3}$

$density = 3002.4 kg/m^3$

so here density of object is 3002.4 kg/m^3

7 0

3 years ago

Read 2 more answers

Describe the conditions that are necessary for mechanical energy to be a conserved quantity.

rusak2 [61]

Mechanical energy is conserved when there are no non-conservative forces acting on the body. Examples are friction and elastic forces of stress in a body. These non-conservative forces convert mechanical energy to other forms of energy like heat and sound

Hope this makes sense

5 0

3 years ago

The record height of a man to date is 8 feet 11 inches (107 inches). If all men had identical body types, their weights would

Alisiya [41]

Answer:

679.08 lbs

Explanation:

Here it is given that

$m\propto h^3$

$m_1$ = Mass of first person = 175 pounds

$h_1$ = Height of first person = 70 inches

$m_2$ = Mass of second person

$h_2$ = Height of second person = 110 inches

$\frac{m_1}{m_2}=\frac{h_1^3}{h_2^3}\\\Rightarrow m_2=\frac{m_1h_2^3}{h_1^3}\\\Rightarrow m_2=\frac{175\times 110^3}{70^3}\\\Rightarrow m_2=679.08\ lb$

The weight of the second person would be 679.08 lbs

5 0

3 years ago

Si se suelta una moneda desde lo alto de una casa, su velocidad inicial es 4 puntos