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3 years ago

I need the answer right now please

Physics

2 answers:

erastova [34]3 years ago

8 0

Answer:

I believe it is A.

Explanation:

Birds need feathers to fly.

Naddik [55]3 years ago

5 0

It’s not A lol it’s B keeps them warm

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The empire state building is 1,450 feet tall. King Kong weighs 20 tons and he climbs to the very top. If he jumps off the top, w

lozanna [386]

Answer:velocity= $93.12m/s$

Explanation:

We shall use conservation of energy to solve this problem

we have

Potential energy of King Kong at top of building = His kinetic energy at the bottom

Potential energy of an object = $m\times g\times h$ = 20000 kg

Where m is mass of an object(20000 kg)

g is accleration due to gravity = 9.81 $m/s^{2}$

h is the height above the surface of earth = 1450 feet = 441.96 meters

Applying values we get

$(P.E)_{TOP}=(20000\times 9.81\times 441.96) Joules\\\\(P.E)_{TOP}= 86712.552KiloJoules$ ......................(i)

Now Kinetic energy is given by

$(K.E)_{Bottom}=\frac{1}{2}mv^{2}$ .......................(ii)

Equating i and ii we get

86712.552 = $\frac{1}{2}mv^{2}$

$v=\sqrt{\frac{2E}{m}}$

Applying values we get

$v=\sqrt{\frac{2\times 86712.552\times 10^{3}}{20\times 10^{3}}}\\\\v= 93.12m/s$

3 0

3 years ago

To view an interactive solution to a problem that is similar to this one, select Interactive Solution 7.24. A 0.0146-kg bullet i

Vinil7 [7]

Answer:

0.25223 seconds.

Explanation:

$m_1$ = Mass of bullet = 0.0146 kg

$m_2$ = Mass of block = 2.55 kg

v = Combined velocity

$u_1$ = Velocity of bullet = 816 m/s

g = Acceleration due to gravity = 9.81 m/s²

As linear momentum is conserved

$m_1u_1 + m_2u_2 =(m_1 + m_2)v$

Now $u_2=v$ as the block (with the bullet in it) reverses direction and rises,

$m_1u_1 + m_2v =(m_1 + m_2)v\\\Rightarrow m_1u_1=(m_1 + m_2)v-m_2v\\\Rightarrow 0.0146\times 816=(0.0146 + 2.55)v-(-2.55v)\\\Rightarrow 11.9136=2.2646v+2.55v\\\Rightarrow 11.9136=4.8146v\\\Rightarrow v=\frac{11.9136}{4.8146}\\\Rightarrow v=2.47447\ m/s$