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3 years ago

11

A bird has a kinetic energy of 3 J and a potential energy of 25 J. What is the mechanical energy of the bird?

1 answer:

rjkz [21]3 years ago

8 0

Answer:

28 j

Explanation:

because when you add you get 28

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A force of 45 newtons is applied on an object, moving it 12 meters away in the same direction as the force. What is the magnitud

NARA [144]

<h2>Answer: 540 J</h2>

Explanation:

The Work $W$ done by a Force $F$ refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.

Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:

$W=(F)(d)$ (1)

In this case both (the force and the distance in the path) are parallel (this means they are in the same direction), so the work $W$ performed is the product of the force exerted to push the box $F=45N$ by the distance traveled $d=12m$ .

Hence:

$W=(45N)(12m)$ (2)

$W=540Nm=540J$

6 0

3 years ago

A car owner forgets to turn off the headlights of his car while it is parked in his garage. If the 12.0-V battery in his car is

avanturin [10]

Answer: 22.6 hours

Explanation:

The power is the measure of the rate of energy.

In this problem, the 12.0 V battery is rated at 51.0 Ah, which means it delivers 51.0 A of current in a time of t = 1 h = 3600 s. The power delivered by the battery can be written as

$P=IV$

where

I is the current

V = 12.0 V is the voltage of the battery

So the energy delivered by the battery can be written as

$E=Pt=VIt$

Where

$It=51.0 A\cdot h = 51.0 A \cdot 3600 s/h=183,600 A\cdot s$

So the energy delivered is

$E=(12.0)(183,600)=2.2\cdot 10^6 J$

At the same time, the headlight consumes 27.0 W of power, so 27 Joules of energy per second; Therefore, it will remain on for a time of:

$t=\frac{2.2\cdot 10^6 J}{27.0 W}=81481 s = 22.6 h$

3 0

3 years ago

Sav [38]

Answer:

388.5J

Explanation:

Given parameters:

Weight = 70N

Height = 5.55m

Unknown:

Gravitational potential energy at the top of the ladder = ?

Solution:

The gravitational potential energy is the energy due to the position of the body.

Gravitational potential energy = Weight x height

So;

Gravitational potential energy = 70 x 5.55 = 388.5J

8 0

2 years ago

A string that passes over a pulley has a 0.341 kg mass attached to one end and a 0.625 kg mass attached to the other end. The pu

dalvyx [7]

Answer:

The frictional torque is $\tau = 0.2505 \ N \cdot m$

Explanation:

From the question we are told that

The mass attached to one end the string is $m_1 = 0.341 \ kg$

The mass attached to the other end of the string is $m_2 = 0.625 \ kg$

The radius of the disk is $r = 9.00 \ cm = 0.09 \ m$

At equilibrium the tension on the string due to the first mass is mathematically represented as

$T_1 = m_1 * g$

substituting values

$T_1 = 0.341 * 9.8$

$T_1 = 3.342 \ N$

At equilibrium the tension on the string due to the mass is mathematically represented as

$T_2 = m_2 * g$

$T_2 = 0.625 * 9.8$

$T_2 = 6.125 \ N$

The frictional torque that must be exerted is mathematically represented as

$\tau = (T_2 * r ) - (T_1 * r )$

substituting values

$\tau = ( 6.125 * 0.09 ) - (3.342 * 0.09 )$

$\tau = 0.2505 \ N \cdot m$

5 0

3 years ago

A falling skydiver has a mass of 105 kg. What is the magnitude of the skydiver's acceleration when the upward force of air resis

LenKa [72]

F-free = m*g - F_air = m*a

F_air = 1.2 * m

a= (105 kg * 9.8 m.s^2 - 5*105) / 105 kg

a = 9.3 m/s

Hope this helps

7 0

3 years ago