x Turn on thread page Beta
 You are Here: Home

# Simple harmonic motion. Range of frequency? watch

1. I'm having trouble with this question. Any tips or hints would be much appreciated.

A platform oscillates in the vertical direction with simple harmonic motion. Its amplitude of oscillation is C. What is the range of frequency of oscillation for a mass placed on the platform toremain in contact with the platform?

I know that x = Acos(wt + ϕ). Where do I go from here?
2. (Original post by rachelweasley)
I'm having trouble with this question. Any tips or hints would be much appreciated.

A platform oscillates in the vertical direction with simple harmonic motion. Its amplitude of oscillation is C. What is the range of frequency of oscillation for a mass placed on the platform toremain in contact with the platform?

I know that x = Acos(wt + ϕ). Where do I go from here?
Let's think about the platform first. We'll use (as you have) to denote vertical displacement. At t = 0, let's assume the platform is at its maximum height, so we can immediately note that . No need for the .

Now think about the acceleration of the platform; you can work that out from the formula for displacement. Notice when the acceleration will be at a maximum.

Now think about what would happen to the object if the platform were not there; it would fall with constant acceleration of magnitude g.

Now put the platform back and think of the condition required for the platform to "pull away" from the object when the motion starts.
3. (Original post by Gregorius)
Let's think about the platform first. We'll use (as you have) to denote vertical displacement. At t = 0, let's assume the platform is at its maximum height, so we can immediately note that . No need for the .

Now think about the acceleration of the platform; you can work that out from the formula for displacement. Notice when the acceleration will be at a maximum.

Now think about what would happen to the object if the platform were not there; it would fall with constant acceleration of magnitude g.

Now put the platform back and think of the condition required for the platform to "pull away" from the object when the motion starts.
I managed to work it out. Thank you so much.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 21, 2015
Today on TSR

### Negatives of studying at Oxbridge

What are the downsides?

### Grade 9 in GCSE English - AMA

Poll
Useful resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE