Answer:
(a) angle record will be 46°
Explanation:
We have given speed = 33 rpm
Time t = 0.23 sec
We know that 1 revolution = 360°
And 1 minute = 60 sec
So 33 revolution/minute
So angle record by vinyl , which is nearly equal to 46
So angle record by vinyl is 46°
So option (a) will be the correct answer
Answer:
Weight needed to balance the bar is
Explanation:
Given the weight of the bar is
The length of the bar is
The weight of the bar will be uniformly distributed over the entire span. We will consider this as a point load acting in the middle of span length, which is at a distance of from both ends.
Now applying momentum equation about balanced load we get, (see attachment)
Answer:
Its speed is maximum and its acceleration is zero
Explanation:
- Concerning the speed:
In a simple harmonic motion, the speed can be determined through the law of conservation of energy. In fact, we have that the total mechanical energy of the system, which is sum of elastic potential energy U and kinetic energy K, is constant:
where k is the spring constant, x is the displacement, m is the mass and v is the speed.
We see that when the displacement is 0, x = 0: this means that the elastic potential energy U is also 0, therefore the kinetic energy K is maximum, and so the speed v is also maximum.
- Concerning the acceleration:
According to Newton's second law, the acceleration of the system is proportional to the net force:
the net force is just the restoring force of the spring, given by Hooke's law:
So, the acceleration is
and we see that when the displacement is zero, x = 0, and so the acceleration is also zero.