Can someone plz help me :'(
2 answers:
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1) 4 forces
2) 165 N
3) 225 N
Explanation:
1)
There are in total 4 forces acting on the bicylist:
- The gravitational force on the byciclist, acting vertically downward, of magnitude , where m is the mass of the bicyclist and g is the acceleration due to gravity
- The normal force exerted by the floor on the bicyclist and the bike, N, vertically upward, and of same magnitude as the gravitational force
- The force of push F, acting horizontally forward, given by the push exerted by the bicylist on the pedals
- The air drag, R, of magnitude R = 60.0 N, acting horizontally backward, in the direction opposite to the motion of the bicyclist
2)
The magnitude of the net force on the bicyclist can be calculated by considering separately the two directions.
- Along the vertical direction, we have the gravitational force (downward) and the normal force (upward); these two forces are equal in magnitude, since the acceleration of the bicyclist along this direction is zero, therefore the net force in this direction is zero.
- Along the horizontal direction, the two forces (forward force of push and air drag) are balanced, since the acceleration is non-zero, so we can use Newton's second law of motion to find the net force on the bicylist:
where
is the net force
m = 75.0 kg is the mass of the bicyclist
is its acceleration
Solving, we find the net force:
3)
In this part, we basically want to find the forward force of push, F.
We can rewrite the net force acting on the bicyclist as
where:
F is the forward force of push
R is the air drag
We know that:
is the net force on the bicyclist
R = 60.0 N is the magnitude of the air drag
Therefore, by re-arranging the equation, we can find the force generated by the bicylicst by pedaling:
Answer:
a) the capacitance is the same for both capacitors.
b) The potential difference between the plates for the capacitor with charge +2q, is double of the one for the capacitor with charge +q.
c) The electric field magnitude between the plates for the capacitor with charge +2q, is double of the one for the capacitor with charge +q
d) The energy stored between the plates for the capacitor with charge +2q, is 4 times the value for the one with charge +q
Explanation:
a) The capacitance of a capacitor, by definition, is as follows:
Appying Gauss' Law to one of plates, it can be showed, that the capacitance (for a parallel plates capacitor) can be expressed as follows:
C = ε*A / d
As it can be seen, it does not depend on the charge. so we conclude that the capacitance must be the same for both capacitors, due to they are identical except for the value of the charge on the plates.
b) By definition, as we said above, the capacitance is equal to the proportion between the charge of one of the plates, and the potential difference between them.
If this proportion must remain the same, and one of the capacitors has the double of the charge than the other, the potential difference must be the double also.
c) Applying Gauss' law, to the surface of one of the plates, and assuming a constant surface charge density σ, it can be showed that the electric field can be calculated as follows:
E*A = Q/ε₀ as σ=Q/A
⇒ E = σ/ε₀
As σ is directly proportional to the charge (being the area A the same), we conclude that the electric field for the capacitor with charge +2q must be the double than the one for the capacitior with charge +q.
c) The electric potential energy, stored between plates of a capacitor, can be written as follows:
If the capacitance remains the same, we can conclude that the electric potential energy for the capacitor with charge +2q, as the charge is raised to the 2nd power, must be 4 times the one for the capacitor with charge +q.
Answer:
The change in potential energy is
Explanation:
From the question we are told that
The magnitude of the uniform electric field is
The distance traveled by the electron is
Generally the force on this electron is mathematically represented as
Where F is the force and q is the charge on the electron which is a constant value of
Thus
Generally the work energy theorem can be mathematically represented as
Where W is the workdone on the electron by the Electric field and is the change in kinetic energy
Also workdone on the electron can also be represented as
Where considering that the movement of the electron is along the x-axis
So
substituting values
Now From the law of energy conservation
Where is the change in potential energy
Thus