I'm having trouble with an SHM?

Question

Right, a mass is moving in SHM on the end of a spring. The question gives me the force constant of the spring, and the amplitude of the motion. Thats all the info it gives.

The question asks, what is the maximum K.E. of this system.

I'm a bit confused because I can't see a way around the problem without knowing either the mass, or the frequency of oscillation

Can anyone give me any pointers?

Answer 1

Work = F * d
Work = Force of the spring * distance mass moves

Work refers to an activity involving a force and movement in the directon of the force. A force of 20 newtons pushing an object 5 meters in the direction of the force does 100 joules of work.

The max KE is the work put into moving the object.

Answer 2

The maximum K.E. of this system (SHM) is equal to the maximum P.E. of the system. This is the key point you need to know about SHM.

The maximum P.E. of SHM is given by Hook's Law:

P.E.(max) = ½kx²

where x is the amplitude of the motion and k is the force constant

Answer 3

If I were in your shoes, I would look at the units given for each number given. Then break them down into basic units. For instance F=ma is a common useful item. If you know the force in newtons then force is equal to mass times accelration. Break it all the way down to basic units.
Kg.m/s/s. Look for an equation that relates the amplitude and the frequency as well. break these down into their basic units.

Identify the units you need to land on and then see if there is a way to divide and/or multiply with the units you have to get to what you need.

I hope this was clear. If not, email me at [e-mail] with more specifics. I will see if I can help.

Good luck and thanks for not asking for the answer but instruction on how to get the answer.

Answer 4

the body have maximum kinetic energy at the mean position, where the potential energy is zero. Hence
the maximum kinetic energy
= the total energy of the system
= 1/2 k r^2
where k is the force constant and r is the amplitude of motion.