Answer:
No. Your friend will not hear the clap when he/she sees it.
Explanation:
It takes time for sound waves to go through a large area. It takes longer if people are in the area rather than it is empty.
Answer:
The time elapses until the boat is first at the trough of a wave is 4.46 seconds.
Explanation:
Speed of the wave, v = 59 km/h = 16.38 m/s
Wavelength of the wave, 
If f is the frequency of the wave. The frequency of a wave is given by :

The time period of the wave is given by :

We need to find the time elapses until the boat is first at the trough of a wave. So, the time will be half of the time period of the wave.

Hence, this is the required solution.
Answer:
C, A and E
Explanation:
In theory you always assume that the prostive is going to the negtive and since C, A and E are in series they all will turn off will turn off
Voltage = current x resistance
since R is doubled, current must reduce by half.
So,
new current = 120/2 = 60mA
Answer:
0.976 c
Explanation:
= velocity of object 1 relative to earth = 0.80 c
= velocity of object 2 relative to object 1 = 0.80 c
= velocity of object 2 relative to earth
Velocity of object 2 relative to earth is given as


= 0.976 c