Answer:
A
Explanation:
If the object is moving at a constant speed, the object isn't accelerating as the velocity doesn't change.
Answer: the minimal force that you need to apply to move the bureau is F = 198.45N
Explanation:
If you want to move an object, you need to apply a force that is bigger than the force of the statical friction.
The force of statical friction can be written as.
Ff = k*N
where k is the coefficient of static friction, in this case, k = 0.45, and N is the normal force between the object and the surface.
In this case, the normal force is the weight of the bedroom bureau, this is:
N = m*g = 45kg*9.8m/s^2 = 441N
Then the force is:
Fr = 0.45*441N = 198.45N
This means that the minimal force that you need to apply to move the bureau is F = 198.45N
and after this point, the force of friction will work wit the kinetic coefficient of friction, that usually is smaller than the statical one.
Answer:
when the object goes from the focal length to twice the focal length the image goes from infinity to twice the focal length, this image is real and inverted
Explanation:
Let's use the constructor equation to describe the image of a concave mirror
1 / f = 1 / p + 1q
where f is the focal length, p and q the distance to the object and the image, respectively
1 /q = 1/f - 1/p
tell us that the image is between the focal and twice the focal, let's calculate the position of the image
for both ends
case 1, distance to the object p = f
1 / q = 1 / f -1 / f
1 / q = 0
q = ∞
the image is in infinity
case2, distance to object p = 2f
1 / q = 1 / f - 1 / 2f
1 / q = 1 / 2f
q = 2f
the image is twice the focal length, the object and the image are at the same point
therefore the image when the object goes from the focal length to twice the focal length the image goes from infinity to twice the focal length, this image is real and inverted
Answer:
Distance between Ryan home and mountain will be 252 miles
Explanation:
Let the distance from home to mountains is d
It is given that it took 7 hours to go mountains from home
Let the speed in going to mountain is v
Then according to question speed in coming from mountain is v+27
And time taken in come from mountain to home is hour
As distance will be same in both case
Distance will be equal to 
So 
v = 36 miles per hour
So distance will be equal to 
