Answer:
its 45 over 6
Explanation:the answer is in the question
While pushing a refrigerator up a ramp, there would be less friction to overcome if you used a dolly because of the wheels. So the efficiency of the ramp would be greater with the use of the dolly.
<u>Explanation:</u>
The ramp provides for a wedge setup, so when the refrigerator is being pushed up the ramp, the friction on the ramp would equally distributed to the refrigerator when pushed wholly as the friction applied is a product of the coefficient of friction with the Normal reaction of the weight in contact with the surface.
Therefore, when the dolly is used, the surface in contact becomes divided and thus, the friction applied would become less due to though coefficient of friction remains the same, the normal reaction of the weight becomes small and so does the applied friction. Therefore, efficiency of the ramp increases as the friction is less and work done is more.
(a) -17 cm
Magnification equation:

where
is the size of the image
is the size of the object
is the distance of the image from the mirror
is the distance of the object from the mirror
In this problem, we have:
p = 51 cm (the object is 51 cm in front of the mirror)

So, we can find q, the image distance:

and the negative sign means the image is virtual.
(b) -25.5 cm
Mirror equation:

where
p = 51 cm
q = -17 cm
Substituting and re-arranging the equation, we find the focal length of the mirror:

and the negative sign is due to the fact it is a convex mirror.
Answer:
THE FIRST ONE YOU SHOULD TELL HIM AND THE LAST ONE YOU SHOUDENT DO BECAUSE HE WILL DO IT AGAIN AND EXPECT OTHERS TO CLEAN UP AFTER HIM
Explanation: