Answer:
(a)
, 
(b) When
, object is slowing down, when
object is speeding up.
Explanation:
(a) To get the velocity function, we need to take the derivative of the position function.

To get the acceleration function, we need to take the derivative of the velocity function.

(b) The object is slowing down when velocity is decreasing by time (decelerating) hence a < 0

On the other hand, object is speeding up when a > 0

Therefore, when
, object is slowing down, when
object is speeding up.
When light crosses the boundary between layers with different densities, the light is refracted. (A).
Answer:
The average net force on the truck is 375 Newtons.
Explanation:
Using Newton's 3rd equation of motion, we have :
×a×s
where, v = final velocity = 25 m/s
u = initial velocity = 20 m/s
a = acceleration
s = distance traveled = 300 m
Using these values in the above equation, we get acceleration = 0.375 m/
Using Newton's second law, we have:
F=m×a
where m = mass = 1000 kg
a= acceleration = 0.375 m/
Putting values we have F=375 N
Answer:
the claim is not valid or reasonable.
Explanation:
In order to test the claim we will find the maximum and actual efficiencies. maximum efficiency of a heat engine can be found as:
η(max) = 1 - T₁/T₂
where,
η(max) = maximum efficiency = ?
T₁ = Sink Temperature = 300 K
T₂ = Source Temperature = 400 K
Therefore,
η(max) = 1 - 300 K/400 K
η(max) = 0.25 = 25%
Now, we calculate the actual frequency of the engine:
η = W/Q
where,
W = Net Work = 250 KJ
Q = Heat Received = 750 KJ
Therefore,
η = 250 KJ/750 KJ
η = 0.333 = 33.3 %
η > η(max)
The actual efficiency of a heat engine can never be greater than its Carnot efficiency or the maximum efficiency.
<u>Therefore, the claim is not valid or reasonable.</u>
Explanation:
I'd love to but we cant talk right now cause its 12:22 am here and I'm gonna sleep now lol.
but let's follow each other.
who knows we might be able to help each other.
whaddya say?
have a good day ♡