Answer:
The magnification is 133X
Explanation:
For a refractor telescope using convex lenses, the overall magnification os calculated as by dividing the focal length of the objective by that of the eyepiece.
So:
Care must be taken with the units, in this case they are in meters and centimeters, they should be converted into the same unit before calculating:
Answer:
19.95 J
Explanation:
The center of mass of the ladder is initially at a height of:
The center of mass of the ladder ends at a height of:
=L/2
So, the work done is equal to the change in potential energy which is:
W = PE =
now
therefore
W = [mgL/2]×[1 - sin(theta)]
W = [(7.30)(9.81)(2.50)/2]×[1-sin(51°)]
solving this we get
W = 19.95 J
(a) 89.8 m
First of all, let's convert the initial speed from km/h into m/s:
During the reaction time of , the car still travels at constant speed, so it covers a distance of
Later, it slows down with acceleration
The distance covered in this second part can be found with the following equation:
where v=0 is the final speed of the car. Solving for S2,
So the total stopping distance is
(b) 79.2 m
This exercise is identical to the first part, except that this time the acceleration is
So, the distance covered while decelerating is
So the total stopping distance is