Answer:
52.9 N, 364.7 N
Explanation:
First of all, we need to resolve both forces along the x- and y- direction. We have:
- Force A (178 N)
- Force B (259 N)
So the x- and y- component of the total force acting on the block are:
A charge of 35.0 μC is placed on conducting sphere A of radius 8.00 cm. Another identical conducting sphere B (radius 8.00 cm) c
1 answer:
Answer:
a) 50μC
b) 37.45 m/s
Explanation:
a) If the spheres are connected the charge in both spheres tends to be equal. This because is the situation of minimum energy.
Thus, you have:
Hence, each sphere has a charge of 50μC.
b) You use the fact that the total work done by the electric force is equal to the change in the kinetic energy of the sphere. Then, you use the following equations:
where you have used the Coulomb constant = 8.98*10^9 Nm^2/C^2
Next, you equal the total work to the change in K:
hence, the speed of the spheres is 37.45 m/s
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3) The work done is D. zero
4) The kinetic energy is B. 180 J
5) The potential energy is A. 120 J
6) The work done depends on B. position
7) The example of non-renewable energy is C. coal
8) The power expended is
9) The efficiency is A. 100%
10) The velocity ratio is 5
Explanation:
3)
The work done by a force acting an object is given by:
where :
F is the magnitude of the force
d is the displacement
is the angle between the direction of the force and the displacement
When the force is applied perpendicular to the direction of motion,
Therefore, the work done is:
4)
The kinetic energy of a body is given by
where
m is the mass of the body
v is its speed
For the girl in this problem, we have
m = 40 kg
v = 3 m/s
Therefore her kinetic energy is
5)
The potential energy of an object is given by
where
m is the mass
is the acceleration of gravity
h is the heigth of the object relative to the ground
For the ball in this problem,
m = 0.4 kg
h = 30 m
So, the potential energy is
6)
A conservative field is a field for which the work done by the field on an object does not depend on the path taken, but only on the initial and final position of the object.
Gravitational and electric fields are examples of conservative fields. In fact:
- When an object is pulled down by gravity (free fall), the work done by the gravitational field only depends on the change in height
between the two points, not on the path taken during the fall
- When an electric charge is pushed by the electric field, the work done by the field depends only on the initial and final position of the charge in the field
For any conservative field, it is possible to define a "potential" function, which represents the energy per unit mass/charge, and depends only on the position of the object.
7.
- Non-renewable energy sources are sources of energy whose rate of consumption is faster than the rate at which they are re-created. Examples of non-renewable sources are coal, oil, natural gas. These energy sources are consumed at a fast rate, while they take million of years to regenerate, so at the current rate they will eventually run out.
- Renewable energy sources are sources of energy that replenish at faster rate than the rate at which it is consumed. Examples of renewable sources are solar energy, wind, hydroelectric power.
Therefore, the example of non-renewable energy in this case is
C. Coal
8.
For an object pushed by a force F and moving at a constant velocity v, the power expended is given by
where F is the force and v is the velocity.
for the rocket in this problem, we have:
F = 10 N is the force propelling the rocket
v = 3000 m/s is its velocity
Substituting into the equation, we find the power expended:
9.
The efficiency of a machine is given by
where
is the energy in input to the machine
is the useful work in output from the machine
For a real machine, the useful work in output is always lower than the energy input, because part of the energy is "wasted" and converted into thermal energy due to the presence of internal frictions. However, for an ideal machine, all the input energy is converted into useful work, so
And therefore the efficiency is
which means 100%.
10.
The velocity ratio of a block and tackle system is the ratio between the distance moved by the effort and the distance moved by the load.
In a block and tackle system, the velocity ratio is also equal to the number of pulleys in the system.
For the system in the problem, there are 5 pulleys: therefore, this means that when the effort moves 5 metres, the load moves 1 metres, therefore the velocity ratio is
Learn more about kinetic and potential energy:
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Answer:
When they are connected in series
The 50 W bulb glow more than the 100 W bulb
Explanation:
From the question we are told that
The power rating of the first bulb is
The power rating of the second bulb is
Generally the power rating of the first bulb is mathematically represented as
Where is the normal household voltage which is constant for both bulbs
So
substituting values
Thus the resistance of the second bulb would be evaluated as
From the above calculation we see that
This power rating of the first bulb can also be represented mathematically as
This power rating of the first bulb can also be represented mathematically as
Now given that they are connected in series which implies that the same current flow through them so
This means that
So when they are connected in series
This means that the 50 W bulb glows more than the 100 \ W bulb
Answer:
The answer is
<h2>84.9 kPa</h2>Explanation:
Using Boyle's law to find the final pressure
That's
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
Since we are finding the final pressure
From the question
P1 = 115 kPa
V1 = 480 mL
V2 = 650 ml
So we have
We have the final answer as
<h3>84.9 kPa</h3>Hope this helps you