All categories

2 years ago

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

Physics

2 answers:

Ahat [919]2 years ago

8 0

Answer:

28 J

Explanation:

Mechanical energy is the sum of kinetic and potential energy in an object that is used to do work. In other words, it is energy in an object due to its motion or position, or both.

In physics, mechanical energy (Emech) is the energy associated with the motion and position of an object usually in some force field.

Therefore:

ME = KE + PE = 25 + 3 = 28 J

daser333 [38]2 years ago

5 0

Answer:

28j

Explanation:

You might be interested in

You've always wondered about the acceleration of the elevators in the 101 story-tall Empire State Building. One day, while visit

love history [14]

To develop this problem we will proceed to convert all units previously given to the international system for which we have to:

$140 lb = 63.5 kg \rightarrow 63.5kg (9.8m/s) =622.3 N$

$120 lb = 54.4 kg \rightarrow 54.4kg (9.8m/s)= 533 N$

$170 lb = 77.1 kg \rightarrow 77.1 kg (9.8m/s) =756 N$

PART A ) From the given values the minimum acceleration will be given for 120Lb and maximum acceleration when 170Lb is reached therefore:

$F = 756 - 622.3$

$F = 133.7N$

Through the Newtonian relationship of the Force we have to:

$F= ma$

$a = \frac{F}{m}$

$a = \frac{133.7}{63.5}$

$a = 2.1m/s^2$

PART B) For the maximum magnitude of the acceleration downward we have that:

$F = 622.3 - 533$

$F = 89.3N$

Through the Newtonian relationship of the Force we have to:

$F= ma$

$a = \frac{F}{m}$

$a = \frac{89.3}{63.5}$

$a = 2.1m/s^2$

$a = 1.04 m/s^2$

7 0

2 years ago

The newly formed xenon nucleus is left in an excited state. Thus, when it decays to a state of lower energy a gamma ray is emitt

nevsk [136]

Answer:3.87*10^-4

Explanation:

What is the decrease in mass, delta mass Xe , of the xenon nucleus as a result of this deca

We have been given the wavelength of the gamma ray, find the frequency using c = freq*wavelength.

C=f*lambda

3*10^8=f*3.44*10^-12

F=0.87*10^20 hz

Then with the frequency, find the energy emitted using equation

E=hf E = freq*Plank's constant

E=.87*10^20*6.62*10^-34

E=575.94*10^(-16)

With this energy, convert into MeV from joules.

With the energy in MeV, use E=mc^2 using c^2 = 931.5 MeV/u.

Plugging and computing all necessary numbers gives you

3.87*10^-4 u.

6 0

2 years ago

A radioactive substance decays exponentially. A scientist begins with 200 milligrams of a radioactive substance. After 17 hours,

lianna [129]

75.17 mg of the radioactive substance will remain after 24 hours.

Answer:

Explanation:

Any radioactive substance will obey the exponential decay behavior. So according to this behavior, any radioactive substance will be decaying in terms of exponential form of disintegration constant and Time.

Disintegration constant is the rate of decay of radioactive elements. It can be measured using the half life time of the radioactive element .While half life time is the time taken by any radioactive element to decay half of its concentration. Like in this case, at first the scientist took 200 mg then after 17 hours, it got reduced to 100 g. So the half life time of this element is 17 hours.

Then Disintegration constant = 0.6932/Half Life time

Disintegration constant = 0.6932/17=0.041

Then as per the law of disintegration constant:

$N = N_{0}e^{-xt}$

Here N is the amount of radioactive element remaining at time t and $N_{0}$ is the initial amount of sample, x is the disintegration constant.

So here, $N_{0}$ = 200 mg, x = 0.041 and t = 24 hrs.

N = 200 × $e^{-24*0.041}$ =75.17 mg.

So 75.17 mg of the radioactive substance will remain after 24 hours.

3 0

2 years ago

A 10. g cube of copper at a temperature T1 is placed in an insulated cup containing 10. g of water at a temperature T2. If T1 &g

Anna35 [415]

Answer:

a. The temperature of the copper changed more than the temperature of the water.

Explanation:

Because we're only considering the isolated system cube-water, the heat of the system should be constant, that implies the heat the cube loses is equal the heat the water gains (because by zero law of thermodynamics heat (Q) flows from hot body to cold body until reach thermal equilibrium and T1>T2). So:

$Q_{cube}=Q_{water}$ (1)

But Q is related with mass (m), specific heat (c) and changes in temperature ( $\varDelta T$ )in the next way:

$Q=cm\varDelta T$ (2)

Using (2) on (1):

$c_{cooper}*m_{cooper}*\varDelta T_{cooper}=c_{water}*m_{waterer}*\varDelta T_{water}$

$(10g)(0.385 \frac{J}{g\,C})(\varDelta T_{cooper})=(10g)(4.186 \frac{J}{g\,C})(\varDelta T_{water})$

$(0.385 \frac{J}{g\,C})(\varDelta T_{cooper})=(4.186 \frac{J}{g\,C})(\varDelta T_{water})$

Because we have an equality and 0.385 < 4.186 then $\varDelta T_{cooper}>\varDelta T_{waterer}$ to conserve the equality

4 0

2 years ago

Two speakers both emit sound of frequency 320 Hz, and are in phase. A receiver sits 2.3 m from one speaker, and 2.9 m from the o

satela [25.4K]

Answer:

Option B

Explanation:

The phase difference is found by subtracting the 2.3m for the receiver from the other speaker which is 2.9m hence

Phase difference= 2.9-2.3= 0.6

3 0

2 years ago