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
A.
According to the equation: v=λ*f
λ stands for wavelength. wavelength increases, the frequency will decrease. lower frequency deserves low energy.
Answer:84Nm
Explanation:
force=400N
Distance=0.210m
Workdone=force x distance
Workdone=400 x 0.210
Workdone=84Nm
Answer:
The tomato won't hit the car
Explanation:
According to the statement, the car moves at constant speed behind the truck fully loaded with tomatoes, and in the same direction. When a tomato falls from the top of the truck, it should not hit the car as the tomato falls due to the force of gravity, while horizontally has the same speed and in the same direction as the truck. So we assume that the tomato will fall to the road without touching the car.
Have a nice day!
Answer:
The force generated by a single muscle fiber can be increased by increasing the frequency of action potentials
Explanation:
The force generated by a muscle fiber is the result of the shortening of the skeletal muscle, and this force is also know as muscle tension. The larger motor units shorten along with the smaller units to produce the muscle force. The time lapsed between the beginning of the action potential in the muscle and the beginning of the contraction is the latent period. Action potential is the result of the difference electrical potential as a result of passage of an impulse along the membrane of a muscle or nerve cell.
