An object has a kinetic energy of 810 J after falling a certain distance. If the mass of the object is 20kg, what is the speed o
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Answer:
1.92 x 10⁻¹²J
Explanation:
The magnetic force from the magnetic field gives the circulating protons gives the particle the necessary centripetal acceleration to keep it orbiting round the circular path. And from Newton's second law of motion, the force(F) is equal to the product of the mass(m) of the proton and the centripetal acceleration(a). i.e
F = ma
Where;
a = [v = linear velocity, r = radius of circular path]
=> F = m ------------(i)
We also know that the magnitude of this magnetic force experienced by the moving charge (proton) in a magnetic field is given by;
F = q v B sin θ ----------(ii)
Where;
q = charge of the particle
v = velocity of the particle
B = magnetic field
θ = the angle between the velocity and the magnetic field.
Combining equations (i) and (ii) gives
m = q v B sin θ [θ = 90° since the proton is orbiting at the maximum orbital radius]
=> m = q v B sin 90°
=> m = q v B
Divide both side by v;
=> m = qB
Make v subject of the formula
v =
From the question;
B = 1.25T
m = mass of proton = 1.67 x 10⁻²⁷kg
r = 0.40m
q = charge of a proton = 1.6 x 10⁻¹⁹C
Substitute these values into equation(iii) as follows;
v =
v = 4.79 x 10⁷m/s
Now, the kinetic energy, K, is given by;
K = mv²
m = mass of proton
v = velocity of the proton as calculated above
K =
K = 1.92 x 10⁻¹²J
The kinetic energy is 1.92 x 10⁻¹²J
Both require time, but velocity requires displacement and speed requires distance.
Explanation:
Speed and velocity are two different quantities. In fact:
- Speed is a scalar quantity, which gives a measure of how fast an object is moving, regardless of its direction. Therefore, it only has a magnitude, which is given by the ratio between distance covered and time taken:
Therefore, speed does not take into account the direction of motion.
- Velocity, on the other hand, is a vector quantity, so it has magnitude and a direction.
The magnitude of the velocity is given by
where displacement is a vector connecting the initial point with the final point of motion of an object.
The direction of the velocity corresponds to the direction of the displacement.
It must be noted also that in certain situations, the average velocity is zero, while the speed is not zero: for example, for an object completing a circle in a certain time interval, its speed is not zero, while its velocity is zero (because the object returns to the starting point, so the displacement is zero.
Therefore, the correct answer is
Both require time, but velocity requires displacement and speed requires distance.
Learn more about speed and velocity:
#LearnwithBrainly
Explanation:
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