You can reason it out like this:
-- The car starts from rest, and goes 8 m/s faster every second.
-- After 30 seconds, it's going (30 x 8) = 240 m/s.
-- Its average speed during that 30 sec is (1/2) (0 + 240) = 120 m/s
-- Distance covered in 30 sec at an average speed of 120 m/s
= 3,600 meters .
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The formula that has all of this in it is the formula for
distance covered when accelerating from rest:
Distance = (1/2) · (acceleration) · (time)²
= (1/2) · (8 m/s²) · (30 sec)²
= (4 m/s²) · (900 sec²)
= 3600 meters.
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When you translate these numbers into units for which
we have an intuitive feeling, you find that this problem is
quite bogus, but entertaining nonetheless.
When the light turns green, Andy mashes the pedal to the metal
and covers almost 2.25 miles in 30 seconds.
How does he do that ?
By accelerating at 8 m/s². That's about 0.82 G !
He does zero to 60 mph in 3.4 seconds, and at the end
of the 30 seconds, he's moving at 534 mph !
He doesn't need to worry about getting a speeding ticket.
Police cars and helicopters can't go that fast, and his local
police department doesn't have a jet fighter plane to chase
cars with.
<span>x=((12.3/100)m)cos[(1.26s^−1)t]
v= dx/dt = -</span><span>((12.3/100)*1.26)sin[(1.26s^−1)t]
v=</span>-((12.3/100)*1.26)sin[(1.26s^−1)t]=-((12.3/100)*1.26)sin[(1.26s^−1)*(0.815)]
v=<span>
<span>-0.13261622 m/s
</span></span>the object moving at 0.13 m/s <span>at time t=0.815 s</span>
Answer :
The number of vacancies (per meter cube) = 5.778 × 10^22/m^3.
Explanation:
Given,
Atomic mass of silver = 107.87 g/mol
Density of silver = 10.35 g/cm^3
Converting to g/m^3,
= 10.35 g/cm^3 × 10^6cm^3/m^3
= 10.35 × 10^6 g/m^3
Avogadro's number = 6.022 × 10^23 atoms/mol
Fraction of lattice sites that are vacant in silver = 1 × 10^-6
Nag = (Na * Da)/Aag
Where,
Nag = Total number of lattice sites in Ag
Na = Avogadro's number
Da = Density of silver
Aag = Atomic weight of silver
= (6.022 × 10^23 × (10.35 × 10^6)/107.87
= 5.778 × 10^28 atoms/m^3
The number of vacancies (per meter cube) = 5.778 × 10^28 × 1 × 10^-6
= 5.778 × 10^22/m^3.
We need a and we have m and F . Now a = f÷m so therefore a = 4,9 ÷ 0,5 which is 0,98 metres per cubic second
Correct option: A
An object remains at rest until a force acts on it.
As the water moves faster, it applies greater force on the sediment, which over comes the frictional forces between the bed and the sediment. So, when the river flows faster, more and larger sediment particles are carried away. When the flow slows down, the river couldn't apply enough force on the larger sediments which can overcome the frictional force between the sediment and the river bed. So, the net force on the heavier particles become zero. Hence, the heavier particles of the load will settle out.
