A football kicked off at an angle 20° from the ground reaches a maximum height of 4.7 m. What is the initial velocity of the kic
1 answer:
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Answer:
b) Betelgeuse would be times brighter than Sirius
c) Since Betelgeuse brightness from Earth compared to the Sun is the statement saying that it would be like a second Sun is incorrect
Explanation:
The start brightness is related to it luminosity thought the following equation:
(1)
where is the brightness,
is the star luminosity and
, the distance from the star to the point where the brightness is calculated (measured). Thus:
b) and
where
is the Sun luminosity (
) but we don't need to know this value for solving the problem.
is light years.
Finding the ratio between the two brightness we get:
c) we can do the same as in b) but we need to know the distance from the Sun to the Earth, which is . Then
Notice that since the star luminosities are given with respect to the Sun luminosity we don't need to use any value a simple states the Sun luminosity as the unit, i.e 1. From this result, it is clear that when Betelgeuse explodes it won't be like having a second Sun, it brightness will be 5 orders of magnitude smaller that our Sun brightness.
Answer:
d = 11.1 m
Explanation:
Since the inclined plane is frictionless, this is just a simple application of the conservation law of energy:
Let d be the displacement along the inclined plane. Note that the height h in terms of d and the angle is as follows:
Plugging this into the energy conservation equation and cancelling m, we get
Solving for d,
Answer:
Speed of the car 1 =
Speed of the car 2 =
Explanation:
Given:
Mass of the car 1 , M₁ = Twice the mass of car 2(M₂)
mathematically,
M₁ = 2M₂
Kinetic Energy of the car 1 = Half the kinetic energy of the car 2
KE₁ = 0.5 KE₂
Now, the kinetic energy for a body is given as
where,
m = mass of the body
v = velocity of the body
thus,
or
or
or
or
or
.................(1)
also,
or
or
or
or
or
or
or
or
and, from equation (1)
Hence,
Speed of car 1 =
Speed of car 2 =