Please, answer the two Pre-Lab Questions. Thanks. Why is it important experiment
ID: 1419368 • Letter: P
Question
Please, answer the two Pre-Lab Questions. Thanks.
Why is it important experimentally that when the mass is revolving at a uniform velocity we make our measurements with the mass hanging vertically? If the mass were revolving at a greater velocity, the spring would be stretched a greater amount How does affect the force exerted by the spring on the mass the a mass to a string and whirl that mass on the string in a big circle over your head The only thing keep that mass from flying off in a straight line is that string You are constancy pulling that mass inward as you swing it around with a force that is transferred along the sting as a tension in the string So the force that the mass experiences is a tension force acting perpendicularly to the mass's velocity The direction of that force is inward towards the center of the circle that you are swinging that mass in This follows with what Newton said for his second law for uniform circular motion If a body is moving at a uniform speed, v, in a circle of radius, r, it experiences a centripetal acceleration, a. The magnitude of this centripetal acceleration is According to Newton's second law, every accelerated body must have a net force acting on it which is given by F ma In the case of uniform circular motion, this force is called the centripetal force and is defined by c-^mv' PI mr F = ma = mv^2/r = 4 n mr/t^2 in this experiment, the centripetal force is supplied by a spring that is fastened between a rotating rod and a suspended mass. For a given mass and radius of rotation, the speed of the mass can be determined by finding the time it requires to travel a set distance. The corresponding centripetal force can then be calculated by using equation 2 The centripetal force is equal to the magnitude of the static force produced by the spring in keeping the mass at a distance equal to the radius of rotation. On the centripetal force apparatus, a movable indicator post is used as a reference point for the radius of rotation of the mass. The mass should always hang directly over the indicator post when the spring is detached and while the mass is not rotated This is so that while the spring is attached and the mass is circling at a constant speed during the experiment that the tension in the string does not add a horizontal force to the situation. Only the spring should supply the horizontal force. Attach the spring back onto the mass in order to do the experiment. The system can be rotated by applying a torque with the fingers to the knurled portions of the center shaft. With a little practice, the rotation can be adjusted to keep the mass passing directly over the indicator. Be sure to adjust the counterbalance so that the rotation is smooth. To obtain v, measure the time required for at least 50 revolutions. This measurement should be done 5 times. Average all five measurements and calculate the centripetal force using MRS units.Explanation / Answer
1). As we will choose equilibrium position, where net torque is zero. From this equilibrium position we can displace the mass, and then we can write restoring torque and accordingly we can write angular velocity and then time period.
Another plus point for that position is that here mass will have least potential energy, we can assume this position to be reference and can proceed accordingly.
2). As velociy mass increases, the centripetal force required for its motion also increases, as centripetal force, F = mv^2/R.
And spring force will balance mg and provide centripetal force.
As spring force is directly proportional to its extension. Hence extension also increases.