Answer:
4.163 m
Explanation:
Since the length of the bridge is
L = 380 m
And the bridge consists of 2 spans, the initial length of each span is

Due to the increase in temperature, the length of each span increases according to:

where
is the initial length of one span
is the temperature coefficient of thermal expansion
is the increase in temperature
Substituting,

By using Pythagorean's theorem, we can find by how much the height of each span rises due to this thermal expansion (in fact, the new length corresponds to the hypothenuse of a right triangle, in which the base is the original length of the spand, and the rise in heigth is the other side); so we find:

Explanation:
The particle will be at rest when its velocity
is equal to zero. Recall that the velocity is simply the derivative of the position
with respect to time:

Since 
then

Solving for t, we find that the particle will be at rest at

Answer:
The magnification is 0.3
Explanation:
Given:
The focal length of the convex mirror, f = 15 cm
for convex mirror f = -f = -15 cm
The distance of object, u = 35 cm
Height of the object, h = 2 cm
Now, using the mirror formula, we have

where, v is the distance of the image
on substituting the values, we get

or

or
v = -10.5 cm
now, the magnification (m) is given as:
m = 
on substituting the values, we get
m = 
or
m = 0.3
Hence, the magnification is 0.3