Answer:
6.5 seconds.
Explanation:
Given: h=-16t²+679
When the object reaches the ground, h=0.
∴ 0=-16t²+679
collecting like terms,
⇒ 16t²=679
Dividing both side of the equation by the coefficient of t² i.e 16
⇒ 16t²/16 = 679/16
⇒ t² = 42.25
taking the square root of both side of the equation.
⇒ √t² =√42.25
⇒ t = 6.5 seconds.
Answer:
False
Explanation:
The direction of magnetic field on a current carrying conductor can be determined by the Fleming's right hand rule where
- The thumb represents the direction of motion
- the index finger represents the direction of field.
- The middle finger is the direction of induced current.
When two conductors carrying currents flowing in opposite direction, the magnetic field will be in the same direction hence they will repel.
<u><em>When the currents in them flow in same direction, then it means the magnetic field will be opposition and there will be a force of attraction between the conductors.</em></u>
Answer:
Explanation:
The motion of the skater is a uniformly accelerated motion, so we can find the deceleration by using the following suvat equation:
where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
In this problem, we have:
u = 19 m/s is the initial velocity of the skater
v = 18 m/s is the final velocity of the skater
s = 2.0 m is the displacement
Solving for a, we can find the acceleration:
And the negative sign tells us that the acceleration is in the opposite direction to the motion (so, it is a deceleration)
At the present time, the only way we know of that light can get shifted
toward the blue end of the spectrum is the Doppler effect ... wavelengths
appear shorter than they should be when the source is moving toward us.
IF that's true in the case of the Andromeda galaxy, it means the galaxy is
moving toward us.
We use the same reasoning to conclude that all the galaxies whose light is red-shifted are moving away from us. That includes the vast majority of all galaxies that we can see, and it strongly supports the theory of the big bang
and the expanding universe.
If somebody ever comes along and discovers a DIFFERENT way that light
can get shifted to new, longer or shorter wavelengths, then pretty much all
of modern Cosmology will be out the window. There's a lot riding on the
Doppler effect !
The north celestial pole (and also the south) are described as two imaginary points that project on the axis of rotation of the earth, indefinitely towards space and that intersects with the celestial sphere (Remember that the earth has a slight inclination with respect to to its axis of rotation). The north and south celestial poles are directly above the head of someone located at the north or south pole of the earth.
Correct Answer is A.
