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3 years ago

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Find the time it takes for an object dropped from a building and reaches a final velocity of 20 m/s downward?

1 answer:

MrRissso [65]3 years ago

6 0

Answer:

Explanation:

v = at

t = v/a

t = 20 m/s / 9.8 m/s²

t = 2.0408163...

t = 2.0 s

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3 years ago

Read 2 more answers

Jack and Jill are maneuvering a 3300 kg boat near a dock. Initially the boat's position is < 2, 0, 3 > m and its speed is

Paraphin [41]

Answer:

The workdone by Jack is $W_{jack} = -1050J$

The workdone by Jill is $W_{Jill} = 0J$

The final velocity is $v = 1.36 m/s$

Explanation:

From the question we are given that

The mass of the boat is $m_b = 3300kg$

The initial position of the boat is $P_i = (2 \r i + 0 \r j + 3\r k)m$

The Final position of the boat is $P_f = (4\r i + 0 \r j + 2\r k )\ m$

The Force exerted by Jack $\r F = (-420\r i + 0 \r j + 210\r k) \ N$

The Force exerted by Jill $\r F_{Jill} =(180 \r i + 0\r j + 360\r k)$

Now to obtain the displacement made we are to subtract the final position from the initial position

$\r P = P_f - P_i$

$= (4\r i + 0\r j + 2 \r k) - (2\r i + 0\r j + 3\r k )$

$= (2\r i + 0\r j -\r k )m$

Now that we have obtained the displacement we can obtain the Workdone

which is mathematically represented as

$W =\r F * \r P$

The amount of workdone by jack would be

$W_{jack} =\r F * \r P$

$= [(-420\r i +0\r j +210\r k)(2\r i + 0\r j - \r k)]$

$= (-420) (2) + (210)(-1)$

$= -840 - 210$

$=-1050J$

The amount of workdone by Jill would be

$W_{Jill} =\r F * \r P$

$= [(180 \r i + 0\r j + 360\r k)(2\r i +0\r j -\r k)]$

$= (180 )(2) +(360)(-1)$

$=0J$

According to work energy theorem the Workdone is equal to the kinetic energy of the boat

$W = K.E = \frac{1}{2} m *[v^2 - (1.1)^2]$

$-1050 = 0.5*3300 [*v^2- (1.1)^2]$

$-1050 = 1650 [v^2 -1.21]$

$0.6363 = v^2 -1.21$

$v^2 = 0.6363+1.21$

$v^2 =1.846$

$v = 1.36\ m/s$

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4 years ago

Two similar sized stones one heavy and one light dropped from the same height into a pond explain why the impact of the heavy st

Zigmanuir [339]

In energy point of view, the larger stone had more potential energy before dropping. impacting the water, the larger one, having more kinetic energy which changed from potential energy, tranfered energy to the water and formed wave. the amplitude of the wave indicate the energy of the wave. more energy more amplitude.

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3 years ago

A moving freight car runs into an identical car at rest on the track. The cars couple together. Compared to the velocity of the

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Answer:

one half as large , initial velocity is two times larger

Explanation:

Momentum is conserved.

p₁ + p₂ = p₁' + p₂'

m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'

m₁ = m₂ =m , v₂= 0

v₁' =v₂'

mv₁ = 2mv₁'

v₁ = 2v₁'

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3 years ago

Un cuerpo de 60 kg se encuentra a una distancia de 3.5 m del otro cuerpo, de manera que entre ellos se produce una fuerza de 6.5

aev [14]

Answer:

1989.6Kg

Explanation:

The computation of the mass of the other body is given below:

As we know that

F = G × m1 × m2 ÷ r²

Here the G would have the constant value i.e. 6.67 × 10^-11Nm² / kg².

Now

6.5 × 10^-7N = 6.67 × 10^-11Nm² / kg² × 60Kg × m2 / (3.5m) ²

m2 = (F × r²) / (G × m1)

m2 = (6.5 × 10^-7N × (3.5m) ²) ÷ (6.67 × 10^-11Nm² / kg² × 60Kg)

= 1989.6Kg

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3 years ago