Answer:
a) 400.4Joules
b) 262.69Joules
Explanation:
Work is said to be done if the force applied to an object cause the object to move through a distance
Workdone = Force × Distance
Given
Force = 76N
Distance= 5.2m
Work done = 77 × 5.2
Work done = 400.4Joules
b) If the force is exerted at an angle of 41°
Work done = Fdsin theta
Work done = 77(5.2)sin41
Work done = 400.4sin41
Work done = 262.69Joules
Density = mass / volume
mass = 1.1 g
volume = length of side ^ 3 = [1.2 * 10^-5 km * 100000 cm/km]^3 = [1.2 cm]^3 = 1.728 cm^3
density = 1.1 g / 1.728 cm^3 = 0.64 g / cm^3
Answer: 71.7 KJ
Explanation:
The rotational kinetic energy of a rotating body can be written as follows:
Krot = ½ I ω2
Now, any point on the rim of the flywheel, is acted by a centripetal force, according to Newton’s 2nd Law, as follows:
Fc = m. ac
It can be showed that the centripetal acceleration, is related with the angular velocity and the radius, as follows:
ac = ω2 r
We know that this acceleration has a limit value, so , we can take this limit to obtain a maximum value for the angular velocity also.
As the flywheel is a solid disk, the rotational inertia I is just ½ m r2.
Replacing in the expression for the Krot, we have:
Krot= ½ (1/2 mr2.ac/r) = ¼ mr ac = ¼ 67.0 Kg. 1.22 m . 3,510 m/s2 = 71. 7 KJ
Answer:
Explanation:
Work done on the lever ( input energy ) = force applied x input distance
= 24 N x 2m = 48 J
Work done by the lever ( output energy ) = load x output distance
= 72 N x 0.5m = 36 J
efficiency = output energy / input energy
= 36 J / 48 J
= 3 / 4 = .75
In percentage terms efficiency = 75 % .
Answer:
Cycles per second is dependent on the construction of the alternator and the 120 volts is dependent upon the current and resistance in the circuit according to the ohms law.
Explanation:
We are given with AC of 120 volts, 20 amperes and 60 hertz frequency.
<u>According to the Ohm's law, we find its resistance:</u>
So, this 6 ohm resistance controls the current controls the magnitude of the AC current, while the frequency of the current remains constant and depends upon the construction and rotational speed of the armature of the alternator producing the current.
Here the value of frequency is the number of times the current changes its direction or the polarity in one second.
