i squared r = 0.03x0.03x1000=3x0.03x10=.9W
Molecules Speed Up because the other three options only occur when the temperature is decreased.
Answer:
The sphere is positively charged
Explanation:
This is because when the positively charged rod is brought near the metal rod A, the electrons in metal rod A and sphere B are attracted towards it into metal rod A while the positive charges in the are repelled into sphere B. So, when the charged rod is withdrawn, and metal rod A and sphere B are separated, metal rod A is now negatively charged, but sphere B is positively charged.
So, sphere B is positively charged.
1. 168.1 Hz
To find the apparent frequency heard by the driver in the car, we can use the formula for the Doppler effect:
where
f is the original sound of the horn
v is the speed of sound
is the velocity of the observer (the driver and the car), which is positive if the observer is moving towards the source and negative if it is moving away
is the velocity of the sound source (the train), which is positive if the source is moving away from the observer and negative otherwise
In this problem we have, according to the sign convention used:
Substituting, we find:
2. 
The speed of light can be calculated as
where
d is the distance travelled
t is the time taken
In this problem:
is the total distance travelled by the laser beam (twice the distance between the Earth and the Moon)
t = 2.60 s is the time taken
Substituting in the formula,
Answer:
the angle of incident is 40°
Explanation:
NQ is the normal to the mirror, therefore
angle NQA =90°
PQA = 50°
incident angle = NQA - PQA
90°- 50° = 40°
note that the angle of reflection is equal to the angle of incident
