When thermal insulation, such as spun glass or rock wool, is placed beneath the roof of a house, then in cold weather the insula
2 answers:
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Answer:
distance between the dime and the mirror, u = 0.30 m
Given:
Radius of curvature, r = 0.40 m
magnification, m = - 2 (since,inverted image)
Solution:
Focal length is half the radius of curvature, f =
f =
Now,
m = -
- 2 = -
= 2 (2)
Now, by lens maker formula:
v = (3)
From eqn (2):
v = 2u
put v = 2u in eqn (3):
2u =
2 =
2(u - 0.20) = 0.20
u = 0.30 m
The car travels at a speed of 25m/s.
<u>Explanation:</u>
Given-
Mass, m = 1500kg
Coefficient of friction, μk = 0.47
Distance, x = 68m
Speed, s = ?
We know,
and
F = μ X m X g
Therefore,
μ * m * g = m * a
μ * g = a
Let, g = 9.8m/s²
So,
We know,
where, v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
If the car comes to rest, the final velocity, v becomes 0.
So,
The car travels at a speed of 25m/s.