Answer: These apparent star tracks are in fact not due to the stars moving, but to the rotational motion of the Earth. As the Earth rotates with an axis that is pointed in the direction of the North Star, stars appear to move from east to west in the sky.

Explanation: why do the star constellations seem to move across the sky

5 0

3 years ago

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Suppose that a car traveling to the west (the - x direction) begins to slow down as it approaches a traffic light. Which stateme

Amanda [17]

Answer:

(A) it's acceleration is negative but but it's velocity is positive

Explanation:

In the question it is given that begins to slow down so its speed is decreasing it is does not means that its speed is negative

For example let first the velocity of the car is 30 m/sec and when its velocity decreases it becomes 20 m/sec in 5 sec

So it is not negative at all

Now the acceleration is the rate of change of velocity

$a=\frac{dv}{dt}$

$a=\frac{v_2-v_1}{dt}=\frac{20-30}{5}=-2 m/sec^2$

So acceleration is negative here

So option (a) will be the correct option

4 0

3 years ago

A child is holding a wagon from rolling straight back down in a driveway that inclined at 20 degree horizontal. if the wagon wei

Digiron [165]

Answer:

F = 51.3°

Explanation:

The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:

$F = Parallel\ Component\ of\ Weight\ of\ Wagon= WSin\theta\\$

where,

W = Weight of Wagon = 150 N

θ = Angle of Inclinition = 20°

Therefore,

$F = (150\ N)Sin\ 20^o$

5 0

3 years ago