Answer:
VAB = 20km/hr
Explanation:
<u>Given the following data;</u>
Velocity of car A, VA = 60km/hr
Velocity of car B, VB = 80km/hr
To find the relative velocity of B w.r.t A, VAB;
Since the two cars are moving in the same direction, we have;
VAB = VB - VA
Substituting into the equation, we have;
VAB = 80 - 60
<em>VAB = 20km/hr</em>
Therefore, the relative velocity of car B with respect to car A is 20 kilometers per hour.
Solution :
Given
Diameter of the roulette ball = 30 cm
The speed ball spun at the beginning = 150 rpm
The speed of the ball during a period of 5 seconds = 60 rpm
Therefore, change of speed in 5 seconds = 150 - 60
= 90 rpm
Therefore,
90 revolutions in 1 minute
or In 1 minute the ball revolves 90 times
i.e. 1 min = 90 rev
60 sec = 90 rev
1 sec = 90/ 60 rec
5 sec = 
= 75 rev
Therefore, the ball made 75 revolutions during the 5 seconds.
Angry sound level = 70 db
Soothing sound level = 50 db
Frequency, f = 500 Hz
Assuming speed of sound = 345 m/s
Density (assumed) = 1.21 kg/m^3
Reference sound intensity, Io = 1*10^-12 w/m^2
Part (a): Initial sound intensity (angry sound)
10log (I/Io) = Sound level
Therefore,
For Ia = 70 db
Ia/(1*10^-12) = 10^(70/10)
Ia = 10^(70/10)*10^-12 = 1*10^-5 W/m^2
Part (b): Final sound intensity (soothing sound)
Is = 50 db
Therefore,
Is = 10^(50/10)*10^-12 = 18*10^-7 W/m^2
Part (c): Initial sound wave amplitude
Now,
I (W/m^2) = 0.5*A^2*density*velocity*4*π^2*frequency^2
Making A the subject;
A = Sqrt [I/(0.5*density*velocity*4π^2*frequency^2)]
Substituting;
A_initial = Sqrt [(1*10^-5)/(0.5*1.21*345*4π^2*500^2)] = 6.97*10^-8 m = 69.7 nm
Part (d): Final sound wave amplitude
A_final = Sqrt [(1*10^-7)/(0.5*1.21*345*4π^2*500^2)] = 6.97*10^-9 m = 6.97 nm
Answer: The correct answer is "No".
Explanation:
Gravity: It is the force which causes object to fall on the earth. It is the force which attracts bodies towards each other.
Potential difference: It is defined as the potential acting between the two points. The work done in moving the unit positive charge from one location to the another location.
The potential difference in battery is caused by the electrodes. There are two terminals in battery: Negative terminal which is at lower potential and Positive terminal which is at higher potential. It forces the electrons to flow in the circuit which constitutes the current.
The gravity and the potential difference have no relation between them.
Therefore, gravity have no effect on the potential difference of a battery.