Acceleration and velocity down a ramp.

[reddevil79]

acceleration and velocity down a ramp. please help!

Homework Statement

Hi, I'm currently studying for my HNC. I'm stuck on an assignment, we performed the old experiment where you roll different objects down a ramp and take the average speed. From the following data we have to work out velocity, inertia, energy etc. I have done something wrong whilst working out the velocity. see below

Ramp height (h) 45mm
ramp length (l) 1800mm

from this I worked out acceleration to be a 0.245 m/s2 using a=gh/l

Homework Equations

v=ta

The Attempt at a Solution

This is where I'm struggling. Am I right in thinking acceleration is constant? If so to get the velocity of each object I've used V=ta
When I do this the object that took the longest down the ramp now has the higher velocity
Nylon solid cylinder = 4.67secs
Steel thin walled cylinder = 5.55secs

Which gives me

V(nylon) 4.67 * 0.245 = 1.14 m/s
V(steel) 5.55 * 0.245 = 1.36m/s

Please help.

Thanks

 

[anathema]

for reaching out for help, I would be happy to assist you with your assignment. Firstly, you are correct in thinking that acceleration is constant down the ramp. This is because the force of gravity acting on the objects is constant and the ramp itself is a smooth surface with no friction.

In order to calculate the velocity of the objects, you need to use the equation v = u + at, where u is the initial velocity (in this case, 0 m/s) and a is the acceleration (0.245 m/s^2). So for the nylon solid cylinder, the velocity would be v = 0 + (0.245)(4.67) = 1.14 m/s. And for the steel thin walled cylinder, the velocity would be v = 0 + (0.245)(5.55) = 1.36 m/s.

Next, to calculate the inertia of each object, you can use the equation I = mr^2, where m is the mass of the object and r is the radius. You should have the mass and radius of each object from your experiment, so you can plug those values in to find the inertia.

Finally, to calculate the energy of each object, you can use the equation E = 1/2mv^2, where m is the mass of the object and v is the velocity. Again, you should have the mass and velocity of each object from your experiment, so you can plug those values in to find the energy.

I hope this helps and clarifies any confusion you had with the velocity calculation. Let me know if you have any further questions. Good luck with your assignment!