Answer: A) converting chemical energy to mechanical energy.
When a muscle contracts, it performs mechanical work. The chemical energy generated in the muscle cell gets converted to mechanical energy. The oxidation of carbohydrates and fats helps in contraction of muscles. The metabolic process generates ATP molecules which is a storehouse of energy. during contraction. These molecules break to generate energy.
Answer:
Some atoms do not have a proton.
Protons have about same mass as electrons.
Protons have the magnitude of charge as neutrons, but are opposite in sign.
Explanation:
Protons are the positive charge particles which are present inside the nucleus and has a mass equal to neutron.
an atom has equal number of electrons and protons hence it is not possible that atom is found in a state where is does not have any proton.
The mass of proton is equal to that of neutron but not electron. Protons are heavier than that of electrons.
Protons are the positively charged particles whereas neutrons do not have any charge present in it.
Hence the selected three options about protons are false.
Answer:
(a) θ= 43.89°
(b) 
Explanation:
Ball 1:
Ball 2:
As the collision is elastic, it means that kinetic energy and momentum are conserved. Following that, we apply the law of conservation of energy and momentum:
and
Where u is the velocity before the collision, and v are the velocities after the collision. Both previous equations can be simplified as:
and
This because the two balls have the same mass. We know that the cue ball is deflected and makes an angle of 30°. From conservation in x-direction, we get::
and
Solving we get:
From conservation in y-direction, we get:
From this, we solve this equation system and get the answers. Remember to add 30° to the angle obtained.
Answer:
A) 443 Hz
B) She has to loosen the string
Explanation:
A) Given;
Beat frequency;f_beat = 3 Hz
Frequency of electronically generated tone; f_e = 440 Hz
We know that formula for beat frequency is given by;
f_beat = |f1 - f2|
Now, applying it to this question, we have;
f_beat = f_v - f_e
Where f_v is frequency of the note played by the violinist
Thus, plugging in the relevant values;
3 = f_v - 440
f_v = 3 + 440
f_v = 443 Hz
B) In the concept of wave travelling in a string, the frequency is directly proportional to the square root of the force acting on the string.
Now, for the violinist to get her violin perfectly tuned to concert A from what it was when she heard the 3-Hz beats, the beat frequency will have to be zero. Which means it has to decrease by 3 Hz. For it to decrease, it means that the force applied has to decrease as we have seen that frequency is directly proportional to the square root of the force acting on the string.
Thus, she would have to loosen the string.
