Explanation:
If you cannot visualize it, just assume that the distance from station A to B is 420km. Each half is 210km.
When the car travels from A to B, it takes 420/30 = 14 hours.
When the car travels from B to the halfway point, it takes 210/30 = 7 hours.
When the car travels from the halfway point to A, it takes 210/70 = 3 hours.
Total time taken = 14 + 7 + 3 = 24 hours.
Total distance = 420km * 2 = 840km.
Hence, the average speed of the car is 840/24 = 35km/h.
Answer:
statement - 'The work done by friction is equal to the sum of the work done by the gravity and the initial push' is correct.
Explanation:
The statement ''The work done by friction is equal to the sum of the work done by the gravity and the initial push" is correct.
The above statement is correct because, the initial push will tend to slide down the block thus the work done by the initial push will be in the downward direction. Also, the gravity always acts in the downward direction. thus, the work done done by the gravity will also be in the downward direction
here, the downward direction signifies the downward motion parallel to the inclined plane.
Now we know that the work done by the friction is against the direction of motion. Thus, the friction force will tend to move the block up parallel to the inclined plane.
Hence, for the block to stop sliding the the above statement should be true.
In a series circuit, the sum of the voltages consumed by each individual resistance is equal to the source voltage. ... In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents flowing through each component.
Answer:
1). 
2). Toward us
3). 
4). Toward us
5). 
6). Away from us
7). 
8). Away from us
Explanation:
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when it is moving away from the observer (that is known as the Doppler effect).
The wavelength at rest is 121.6 nm (
)
Then, for this particular case it is gotten:
Star 1: 
Star 2: 
Star 3: 
Star 4: 
Star 1:
Toward us
Star 2:
Toward us
Star 3:
Away from us
Star 4:
Away from us
Due to that shift the velocity of the star can be determine by means of Doppler velocity.
(1)
Where 
is the wavelength shift, 
is the wavelength at rest, v is the velocity of the source and c is the speed of light.
(2)
<em>Case for star 1 
:</em>
<em></em>
Notice that the negative velocity means that is approaching to the observer.
<em>Case for star 2 
:</em>
<em>Case for star 3 
:</em>
<em>Case for star 4 
:</em>
Answer:
Explanation:
Using the equation of motion v² = u²+2as
v is the final velocity = 40m/s
u is the iniyail velocity 0m/s
a is the acceleration
s is the displacement
Substituting in the formula;
40² = 0²+2a(50)
1600 = 100a
Divide both sides by 100
100a/100 = 1600/100
a = 16
Hence the car acceleration is 16m/s²
