<span>The photoelectric effect is about electrons being ejected from metals when light is shined on metals. The electrons do not behave like waves in the photoelectric effect. Black body radiation is all about the radiation emitted by warm bodies and not about those bodies behaving like waves. The emission spectra of atoms is all about what light is given off by atoms when electrons in those atoms jump down to lower energy levels from higher levels. That also has nothing to do with matter behaving as a wave. Interference is classically defined as the generation of a new wave with an amplitude modulated according to the waves that interfere to form that new wave. Note its emphasis on the wave part.</span>
Answer:
Potential energy plus kinetic energy equals mechanical energy because mechanical energy is basically just all of an object's energy, it's just two kinds of energy. The potential is stored inside and kinetic is being used. Both of those together is the total amount of the objects energy, which is the mechanical energy.
Explanation:
Answer:
m = 4
Explanation:
We have,
You apply a force of 600 N to the branch which acts as a lever. It means it is input force, IF = 600 N
The rear of the truck weighs 2,400 N. It means it is output force, OF = 2400 N
The ratio of output force to the input force is equal to the mechanical advantage of the lever arm. It is given by :

So, the mechanical gain of the lever arm is 4.
Answer:
1)
is<u> positive.</u>
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2) 
Explanation:
<h2><u>
Part 1:</u></h2>
<u></u>
The charged rod is held above the balloon and the weight of the balloon acts in downwards direction. To balance the weight of the balloon, the force on the balloon due to the rod must be directed along the upwards direction, which is only possible when the rod exerts an attractive force on the balloon and the electrostatic force on the balloon due to the rod is attractive when the polarities of the charge on the two are different.
Thus, In order for this to occur, the polarity of charge on the rod must be positive, i.e.,
is <u>positive.</u>
<u></u>
<h2><u>
Part 2:</u></h2>
<u></u>
<u>Given:</u>
- Mass of the balloon, m = 0.00275 kg.
- Charge on the balloon,

- Distance between the rod and the balloon, d = 0.0640 m.
- Acceleration due to gravity,

In order to balloon to be float in air, the weight of the balloom must be balanced with the electrostatic force on the balloon due to rod.
Weight of the balloon, 
The magnitude of the electrostatic force on the balloon due to the rod is given by

is the Coulomb's constant.
For the elecric force and the weight to be balanced,

Answer:
The car appears to be moving 30 km/hr in the opposite direction of the bus.
Explanation: