Answer:
Explanation:
distance covered by ice cube = 0.5 m
force acting downwards = mgsin49
force of friction acting along surface upwards
= mgcos49 x .16 ( reaction force of inclined surface R = mgcos49.)
net force acting downwards
mgsin49 - mgcos49 x .16
mg (sin49 - cos49 x .16 )
net acceleration downwards
g (sin49 - cos49 x .16 )
= (.7547 - .105 ) x 9.8
= 6.367 m / s²
s = ut + 1/2 at²
0.5 = 0 + 1/2 x 6.367 x t²
t² = .1570
t = .4 s
b )
Let required inclination be θ
in the second case net acceleration
a = g ( sin θ - .385 cosθ )
s = ut + 1/2 at²
0.5 = 0 + 1/2 x g ( sin θ - .385 cosθ ) x .4 x .4
( sin θ - .385 cosθ ) = .6377
sin θ = .385 cosθ + .6377
θ = 58 degree.
Answer:
3. Work
Explanation:
Number 1 isn't correct because you are not using efficiency to hold books and walk across the room.
Number 2 could be correct but isn't in this situation because you use power only to hold the books but not to walk across the room.
Number 4 is not correct because you need to do work to do something.
Explanation:
someone to check if the answer is correct
The amount or cost that the user of the energy-efficient bulb save during 100h of use will be $0.319.
<h3>How to calculate the cost?</h3>
For the 11.0W bulb, it should be noted that the value will be:
= 11.0 × 100 × (1/1000) × 0.110
= $0.121
The 40W bulb will be:
= 40 × 100 × (1/1000) × 0.110
= $0.44
Therefore, the amount that will be saved will be:
= $0.44 - $0.121
= $0.319
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We can't see black holes because D) no light can get out
Explanation:
Black holes are the result of the gravitational collapse of a supermassive star.
The life of a supermassive star ends with a huge explosion, called supernova, that leaves behing a super-dense core called black hole.
Black holes are the most dense objects of the universe, having a huge mass in a super small size. For this reason, the gravitational force exerted by a black hole in its proximity is so strong that even light is not able to escape from the gravitational field. For this reason, light from a black hole is not able to reach us, and so we are not able to see these objects.
The "edge" of space beyond which light remains "trapped" inside the black hole is called event horizon, and no object can escape this region of space.
The radius of the event horizon of a black hole is called Schwarzschild radius and it is given by:
where
G is the gravitational constant
M is the mass of the black hole
c is the speed of light
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