A 0.5kg bird has a PE of 137.2 J. What height is its perch?

A 2000-kg truck is being used to lift a 400-kg boulder B that is on a 50-kg pallet A. Knowing the acceleration of the rear-wheel

anzhelika [568]

Answer:

(a) reaction at each front wheel is 5272N (upward)

(b) force between boulder and pallet is 4124N (compression)

Explanation:

Acceleration of the truck $a_{t$ = 1 m/ $s^{2}$ (to the left)

when the truck moves 1 m to the left, the boulder is B and pallet A are raised 0.5 m, then,

$a_{A}$ = 0.5 m/ $s^{2}$ (upward) , $a_{B}$ = 0.5 m/ $s^{2}$ (upward)

Let T be tension in the cable

pallet and boulder: ∑fy = ∑(fy)eff = 2T- ( $m_{A}$ + $m_{B}$ )g = ( $m_{A}$ + $m_{B}$ ) $a_{B}$

= 2T- (400 + 50)*(9.81 m/ $s^{2}$ ) = (400 + 50)*(0.5 m/ $s^{2}$ )

T = 2320N

Truck: $M_{R}$ = ∑( $M_{R}$ )eff: = $-N_{f}$ (3.4m) + $m_{T}$ (2.0m) - T (0.6m)= $m_{T} a_{T}$ (1.0m)

Nf = (2.0m)(2000 kg)(9.81 m/ $s^{2}$ )/3.4m - (0.6 m)(2320 N)/3.4m + (1.0 m)(2000 kg)(1.0 m/ $s^{2}$ ) = 11541.2N - 409.4N - 588.2N = 10544N

∑fy (upward) = ∑(fy)eff: $N_{f}$ + $N_{R}$ - $m_{T}$ g = 0

10544 + $N_{R}$ - (2000kg)(9.81 m/ $s^{2}$ ) = 0

$N_{R}$ = 9076N

∑fx (to the left) = ∑(fx)eff: $F_{R}$ - T = $m_{T} a_{T}$

$F_{R}$ = 2320N + (2000kg)(9.81 m/ $s^{2}$ ) = 4320N

(a) reaction at each front wheel:

1/2 $N_{f}$ (upward): 1/2 (10544N) = 5272N (upward)

(b) force between boulder and pallet:

∑fy (upward) = ∑(fy)eff: $N_{B}$ + $M_{B}$ g - $m_{B}$ $a_{B}$

$N_{B}$ = (400kg)(9.81 m/ $s^{2}$ ) + (400kg)(0.5 m/ $s^{2}$ ) = 4124N (compression)

3 0

4 years ago

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Does solar/light energy explain why/how thing keep going?

KengaRu [80]

Answer:

In 1954 modern solar cells were invented at Bell Labs with the intent of powering satellites. For many years solar remained expensive but today prices have come down and solar electricity is everywhere. Our satellites and the Mars rover are solar powered, as are homes, toys, outdoor lighting and solar battery packs to charge our electronic devices. Importantly solar electricity is bringing light to the one billion people around the world who live without power. Often these solar lights are replacing kerosene or candles as light sources in the home. Let’s look at some frequently asked questions about solar lights and how they are changing the world.

What are solar lights made of? Solar lights are made up of four main components: the solar photovoltaic (PV) panel, battery, control electronics and the light fixture. When the sun is out, a solar panel takes the light from the sun and produces electrical energy. The energy can then be used immediately or stored in a battery. The goal of most solar lights is to provide power at night, so they will definitely contain a battery, or be capable of attaching to a battery. The battery itself may not need to have a large capacity, due to the availability of solar energy, but it should be long lasting to account for difficulties replacing batteries in many places across the globe.

The advent of the Light Emitting Diode (LED) for the light fixture has drastically reduced the capacity needs of both the solar panels and the batteries. They use significantly less energy than other types of lighting, so the solar panel and battery can be smaller (more transportable and less expensive). The control electronics are required to move the energy around the system, keep the system safe, and potentially switch on or off your light, depending on the level of light it’s exposed to. Solar lights made for outdoor lighting will often turn on automatically when it gets dark outside. Some solar lights made for reading will turn off during daylight hours to preserve the solar charge, but won’t turn on until they are powered on by a user.

How is solar energy produced? Let’s look a little more deeply into the science behind solar electricity. Solar energy is produced due to the photovoltaic effect. A photovoltaic panel (also known as solar cell) converts sunlight into electrical energy. The solar cell is made up of multiple layers of crystalline silicon and chemicals that create layers of negatively-charged electrons and positively-charged spaces. When light passes through the solar cell, it excites the negatively-charged electrons and pushes them into the positively-charged spaces. Those spaces then transfer the electron stream as direct current of electricity through the wires in the solar cell for use or to a battery where the power is stored until it is needed.

Explanation:

6 0

3 years ago

How fast would you have to jump off the ground in order to jump at least 10 meters in the air?

ivanzaharov [21]

Answer:

30.5

Explanation:

because you will basically have to be like flash

3 0

4 years ago

Four students are carrying out different laboratory procedures.

leva [86]

B. Jason's experiment

3 0

4 years ago

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Forces in a Three-Charge System Coulomb's law for the magnitude of the force F between two particles with charges Q and Q′ separ

Dmitriy789 [7]

Answer:

Explanation:

Given the charges.

Q1=-17.5nC. Negative charge

Q2=32.5nC. Positive charge

Q3=55nC. Positive charge

Q1 is at a distance of -1.68m on the x-axis

Q2 is at the origin i.e at 0m

Q3 is at between Q1 and Q2 at -1.085m on the x-axis

It shows that,

Q1 is at -1.085+1.68 =0.595m from Q3

Also, Q2 is at 1.085m from Q3.

K=9×10^9Nm²/C²

We need to find the net force on Q3

Then we need F13 and F23

Firstly F13

Between Q1 and Q3

There will be attraction i.e, Q3 will move to the negative direction of the x axis, then F13 will be in negative direction

So,

F13=kQ1Q3/r²

F13=9E9×17.5E-9×55E-9/0.595²

F13=2.45×10^-5N

In vector form

F13=—2.45×10^-5N i

Now, we need F23,

This will the force of repulsion because they are both positive charge, the the charge Q3 will move to the negative direction of x axis, since Q2 is at the origin and Q3 is at negative x axis. So, F23 will be negative

F23=kQ2Q3/r²

F23=9E9×32.5E-9×55E-9/1.085²

F23=1.367×10^-5N

In vector form

F23=—1.367×10^-5N i

Then the net force is given as

Fnet = F13+F23

Fnet=—2.45×10^-5Ni—1.367×10^-5Ni

Fnet=—3.82×10^-5N i

Magnitude for the Fnet is

Fnet=3.82×10^-5N.

And the direction

θ= arctan(y/x).

y=0 and x=3.82×10-5

θ= arctan(0/-3.82E-5)

θ=arctan(-0)

θ= 0. in the negative direction, i.e 180°.

3 0

3 years ago