Answer:
last answer
Explanation:
gripping it with the blade facing downward is the most efficient and safe way to use an exacto knife
Answer:
The marble was moving in a projectile and the speed of the engine was 2.716 m/s
Explanation:
The vertical component of the marble's flight path relative to the train
is given by the equation y(t) = v*t - (4.9)*t^2,
where, v is the initial upward velocity of the marble relative to the train.
So with y(1) = v - 4.9 = 0 we have
v = 4.9 m/s.
The marble will reach maximum height after 0.5 seconds, at which the
height will be y(0.5) = (4.9)*(0.5) - (4.9)*(0.5)^2 = (4.9)*(0.25) = 1.225 m.
Now, the marble has a vertical velocity component of 4.9 m/s and a horizontal velocity component
of V m/s such that tan(61) = 4.9 / V
V = 4.9 / tan(61) = 2.716 m/s
This horizontal velocity component of the marble is the same as the
speed of the train i.e. 2.716 m/s.
The braking force is -400 N
Explanation:
We can solve this problem by using the impulse theorem, which states that the impulse applied on the ferry (the product of force and time) is equal to its change in momentum:

where in this problem, we have:
F is the force applied by the brakes
is the time interval
m = 13,000 kg is the mass of the ferry
u = 2.0 m/s is the initial velocity
v = 0 is the final velocity
And solving for F, we find the force applied by the brakes:

where the negative sign indicates that the direction is backward.
Learn more about impulse:
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Answer:
a) W=2.425kJ
b) 
c) 
d) Q=-2.425kJ
Explanation:
a)
First of all, we need to do a drawing of what the system looks like, this will help us visualize the problem better and take the best possible approach. (see attached picture)
The problem states that this will be an ideal system. This is, there will be no friction loss and all the work done by the object is transferred to the water. Therefore, we need to calculate the work done by the object when falling those 10m. Work done is calculated by using the following formula:

Where:
W=work done [J]
F= force applied [N]
d= distance [m]
In this case since it will be a vertical movement, the force is calculated like this:
F=mg
and the distance will be the height
d=h
so the formula gets the following shape:

so now e can substitute:

which yields:
W=2.425kJ
b) Since all the work is tansferred to the water, then the increase in internal energy will be the same as the work done by the object, so:

c) In order to find the final temperature of the water after all the energy has been transferred we can make use of the following formula:

Where:
Q= heat transferred
m=mass
=specific heat
= Final temperature.
= initial temperature.
So we can solve the forula for the final temperature so we get:

So now we can substitute the data we know:

Which yields:

d)
For part d, we know that the amount of heat to be removed for the water to reach its original temperature is the same amount of energy you inputed with the difference that since the energy is being removed this means that it will be negative.

An example for ruining a biodiversity is fishing.
The two factors that have
contributed to increased fishing in deep ocean waters in recent years are the
human population growth and decreased fishing opportunities inshore. Increase
population growth increases the demand for food which also leads to increase in
fish demand. Because the fish demand is high, inshore fishing opportunities
decrease that is why deep ocean waters is the new venue for fishing. This may sound absurd but poaching for subsistence is likely to be less damaging to he biodiversity <span>of an area than poaching for profit. Because the people do not care anymore to the biodiversity that they interrupted just to get back more profit. They do not care what must be taken from it like getting bigger fishes and leaving the smaller ones behind to maintain productivity.</span>