Answer:
Density of rock piece = 2.7 g/cm³
Explanation:
Given:
Volume of rock piece = 18 cm³
Mass of rock piece = 48.6 gram
Find:
Density of rock piece
Computation:
We know relation between density, mass and volume,
Density = Mass / Volume
Density of rock piece = Mass of rock / Volume of rock
Density of rock piece = 48.6 / 18
Density of rock piece = 2.7 g/cm³
Answer:
The applied force is greater than the frictional force.
Explanation:
the chair moves at <u>a constant speed</u><u> </u><u>therefore</u><u>,</u><u> </u><u>the</u><u> </u><u>answer</u><u> </u><u>is</u><u> </u><u>not</u><u> </u><u>A</u><u> </u><u>or</u><u> </u><u>C</u><u>.</u>
if there is no friction then the chair <u>would accelerate and it would not be at a constant speed</u><u>.</u>
hence, the only possible answer is B.
If the force were constant or increasing, we could guess that the speed of the sardines is increasing. Since the force is decreasing but staying in contact with the can, we know that the can is slowing down, so there must be friction involved.
Work is the integral of (force x distance) over the distance, which is just the area under the distance/force graph.
The integral of exp(-8x) dx that we need is (-1/8)exp(-8x) evaluated from 0.47 to 1.20 .
I get 0.00291 of a Joule ... seems like a very suspicious solution, but for an exponential integral at a cost of 5 measly points, what can you expect.
On the other hand, it's not really too unreasonable. The force is only 0.023 Newton at the beginning, and 0.000067 newton at the end, and the distance is only about 0.7 meter, so there certainly isn't a lot of work going on.
The main question we're left with after all of this is: Why sardines ? ?
Answer
given,
time = 10 s
ship's speed = 5 Km/h
F = m a
a is the acceleration and m is mass.
In the first case
F₁=m x a₁
where a₁ = difference in velocity / time
F₁ is constant acceleration is also a constant.
Δv₁ = 5 x 0.278
Δv₁ = 1.39 m/s

a₁ = 0.139 m/s²
F₂ =m x a₂
F₃ = F₂ + F₁
Δv₃ = 19 x 0.278
Δv₃ = 5.282 m/s
a₃=Δv₂ / t

a₃ = 0.5282 m²/s
m a₃=m a₁ + m a₂
a₃ = a₂ + a₁
0.5282 = a₂ + 0.139
a₂=0.3892 m²/s
F₂ = m x 0.3892...........(1)
F₁ = m x 0.139...............(2)
F₂/F₁
ratio = 
ratio = 2.8
3. It is not changing at that time
Explanation:
If the acceleration of a body is zero at some instant in time, it implies that the velocity is not changing at that point in time. Velocity is the rate of change of displacement with time.
✓Acceleration and velocity shares a very close relationship.
✓ For a body to accelerate, the velocity must change. Acceleration is defined as the rate of change of velocity with time.
✓If at any point, a body moves with constant velocity i.e the velocity does not change with time, the acceleration becomes zero.
✓ For acceleration to occur, a body must change velocity.
Learn more:
Acceleration brainly.com/question/6323625
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