What kind of map might have diagrams of air pressure?

A machine that operates a ride at the fair requires 2500 J to lift a 294 N child 5.0 m. What is the efficiency of this machine?

NeX [460]

Answer:

η = 58.8%

Explanation:

Work is defined as the force applied by the distance traveled by the body.

$W =F*d$

where:

W = work [J] (units of joules)

F = force = 294 [N]

d = distance = 5 [m]

$W = 294*5\\W = 1470 [J]\\$

Efficiency is defined as the energy required to perform an activity in relation to the energy actually added to perform some activity. This can be better understood by means of the following equation.

$efficiency = W_{done}/W_{required}\\efficiency = 1470/2500\\efficiency = 0.588 = 58.8%$

5 0

2 years ago

The speed of a tennis ball that is served is 73.14 m/s. During a serve, the ball typically starts from rest and is in contact wi

Serga [27]

Answer: Third option

F = 250w

Explanation:

The impulse can be written as the product of force for the time interval in which it is applied.

$I = F (t_2-t_1)$

You can also write impulse I as the change of the linear momentum of the ball

$I = mv_2 -mv_1$

So:

$F (t_2-t_1) = mv_2 -mv_1$

We want to find the force applied to the ball. We know that

$(t_2-t_1) = 30$ milliseconds = 0.03 seconds

The initial velocity $v_1$ is zero.

The final speed $v_2 = 73.14\ m / s$

So

$F * 0.03 = 73.14m$

$F * 0.03 = 73.14m\\\\F=\frac{73.14m}{0.03}\\\\F=2438m$

We must express the result of the force in terms of the weight of the ball.

We divide the expression between the acceleration of gravity

$g = 9.8\ m / s ^ 2$

$F=\frac{2438m*g}{g},\ \ m*g=w\\\\g=9.8\ m/s^2\\\\F=\frac{2438w}{9.8}\\\\F=249w$

The answer is the third option

3 0

3 years ago

Two objects, P and Q, have the same mo-<br> mentum. Q can have more kinetic energy<br> than P if it:

Art [367]

Answer:

Both the third and fifth answers are correct

8 0

2 years ago

Develop an algebraic relationship that describes a satellite moving in a circular orbit around a planet if the speed of the sate

lana [24]

Answer:

Explanation:

For this problem we must use Newton's second law where force is gravitational attraction

F = m a

Since movement is circular, acceleration is centripetal.

a = v2 / r

Let's replace

G m M / r² = m v² / r

G M r = v²

The distance r is from the center of the planet

r = R + h

v = √ GM / (R + h)

If the friction force is not negligible

F - fr = m a

Where the friction force must have some functional relationship, for example

Fr = b v + c v² +…

Suppose we are high enough for the linear term to derive the force of friction

G m M / r - (m b v + m c v2) = m v2

G M / r - b v = v²

We see that the solution of the problem gives lower speeds and that change over time.

To compensate for this friction force, the motors should be intermittently suspended to recover speed.

5 0

3 years ago

The drawing shows Robin Hood (mass = 85.0 kg) about to escape from a dangerous situation. With one hand, he is gripping the rope

mixas84 [53]

The resultant force on the system is equivalent to the difference in the weights of the chandelier and Robin Hood.
F(net) = 240g - 85g
F(net) = 155g

Robin Hood's Acceleration:
F = ma
155g = 85a
a = 17.89 m/s²

Tension = mg + ma
Tension = 85(g + a)
Tension = 2400 N

8 0

2 years ago