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2 years ago

A coin is dropped in a 15.0 m deep well.

Physics

1 answer:

labwork [276]2 years ago

7 0

Answer:

t = 1.75

t = 0.04

Explanation:

For part 1 we want to use a kenamatic equation with constant acceleration:

X = 1/2*a*t^2

isolate time

t = sqrt(2X / a)

Plugin known variables. Acceleration is the force of gravity which is 9.8 m/s^2

t = sqrt(2*15m / 9.8m/s^2)

t = 1.75 s

The speed of sound travels at a constant speed therefore we don't need acceleration and can use the equation:

v = d / t

isolate time

t = d / v

plug in known variables

t = 15m / 340m/s

t = 0.04 s

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A steam engine absorbs 4 x 105 J and expels 3.5 x 105 J in each cycle. What is its efficiency?

Wewaii [24]

Input heat, Qin = 4 x 10⁵ J
Output heat, Qout = 3.5 x 10⁵ J

From the first Law of thermodynamics, obtain useful work performed as
W = Qin - Qout
= 0.5 x 10⁵ J

By definition, the efficiency is
η = W/Qin
= 100*(0.5 x 10⁵/4 x 10⁵)
= 12.5%

Answer: The efficiency is 12.5%

3 0

2 years ago

The temperature at a point (x, y) on a flat metal plate is given by T(x, y) = 54/(7 + x2 + y2), where T is measured in °C and x,

ANTONII [103]

Answer:

dt/dx = -0.373702

dt/dy = -1.121107

Explanation:

Given data

T(x, y) = 54/(7 + x² + y²)

to find out

rate of change of temperature with respect to distance

solution

we know function

T(x, y) = 54 /( 7 + x² + y²)

so derivative it x and y direction i.e

dt/dx = -54× 2x / (7 +x² + y²)² .........................1

dt/dy = -54× 2y / (7 + x² + y²)² .........................2

now put the value point (1,3) as x = 1 and y = 3 in equation 1 and 2

dt/dx = -54× 2(1) / (7 +(1)² + (3)²)²

dt/dx = -0.373702

and

dt/dy = -54× 2(3) / (7 + (1)² + (3)²)²

dt/dy = -1.121107

7 0

2 years ago

Khaled said the North star is special because it appears all over the world and its changes position.

saw5 [17]

False the North Star never changes it position

3 0

2 years ago

A 170 kg astronaut (including space suit) acquires a speed of 2.25 m/s by pushing off with his legs from a 2600 kg space capsule

saw5 [17]

Explanation:

Mass of the astronaut, m₁ = 170 kg

Speed of astronaut, v₁ = 2.25 m/s

mass of space capsule, m₂ = 2600 kg

Let v₂ is the speed of the space capsule. It can be calculated using the conservation of momentum as :

initial momentum = final momentum

Since, initial momentum is zero. So,

$m_1v_1+m_2v_2=0$

$170\ kg\times 2.25\ m/s+2600\ kg\times v_2=0$

$v_2=-0.17\ m/s$

So, the change in speed of the space capsule is 0.17 m/s. Hence, this is the required solution.

8 0

2 years ago

Car a with mass 1,783 kg collides with stationary 1600 kg car b. they become locked together after the collision and move with s

ValentinkaMS [17]

The initial speed of car A is 15.18 m/s.

Momentum is defined as mass in motion. If there are two objects (the two objects in motion or only one object in motion and the other in stationary) that collide and no other forces work in the system, the law of momentum conservation applies in the system.

p=p'

pa+pb = pa'+pb'

(ma×va) + (mb×vb) = (ma×va') + (mb×vb')

ma = mass of object A (kg) = 1,783 kg
mb = mass of object B (kg) = 1,600 kg
va = speed of object A before collides (m/s)
va' = speed of object A after collides (m/s) = 8 m/s
vb = speed of object B before collides (m/s) = 0 m/s
vb' = speed of object B after collides (m/s) = 8 m/s
p = momentum before collision (Ns)
p' = momentum after collision (Ns)

(ma×va) + (mb×vb) = (ma×va') + (mb×vb')

(1,783×va) + (1,600×0) = (1,783×8) + (1,600×8)

(1,783×va) + 0 = 14,264+12,800

(1,783×va) = 27,064

$va \:=\: \frac{27,064}{1.783}$

va = 15.18 m/s

Learn more about The law of momentum conservation here: brainly.com/question/7538238

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3 0

9 months ago