Part A: Measurements: 1. V0 = 19.1 cm/s delta X = 82 cm\' 2. V0 = 23.2 cm/s delt
ID: 1337479 • Letter: P
Question
Part A:
Measurements:
1. V0 = 19.1 cm/s delta X = 82 cm'
2. V0 = 23.2 cm/s delta x = 111cm
3. v0= 12.3 cm/s delta x = 57 cm
4. V0= 26.1 cm/s delta x =127 cm
5. V0= 31.6 delta x = 160 cm
Determine the friction force f, based your measurements of vo and s.
• For each of your trials, calculate the initial kinetic energy of the cart K0 using: = K = 1/2 mv^2
• Use: = W= F . S = Fscostheta & Wtot = delta K
• Assume that the friction force is directly opposite the cart’s displacement ( = 180)
• Typical values of f are between 0.01 N and 0.1 N
Part B
friction f = .0436/2
measurements: theta = 1.8 degrees
m1 = 523.2
m2 = 40.4 g
theta initial = 4.1
delta x = 140 cm
1. 107.5 cm/s
2. 107.5 cm/s
3. 108.6 cm/s
Page 3: Analysis (Part B – pulling uphill)
• Use = w= FS cos theta to derive a formula for the total work done by the system by all the
forces acting on the two masses. Your formula should be expressed in terms of g, the friction force f, the
inclination (or declination) angle , and the two masses.
• Set Wtot = 0 and calculate the angle. Compare to the experimental value of 0 with a percent difference.
• For your speed measurements, calculate the final kinetic energy K of the system (remember that both
masses are moving). The initial kinetic energy is zero, so the work-energy theorem predicts that K should
be equal to Wtot. Compare these quantities with a percent difference.
Part C
measurements:
theta = 2.1
1. 149.2 cm/s
2.149.2 cm/s
3. 149.2 cm/s
Take the same approach as part B (the only difference being that the cart rolled downhill instead of uphill).
Answer clearly and completely. Written or typed explanations, written calculations, and diagrams are all
appropriate.
Question #1
When you calculated the work done on the cart, you considered the effects of gravity and friction, but not the
force of contact between the cart and the ramp (“normal force”). Why can you ignore the work done by this force?
Question #2
The friction force f was assumed to be the same for the tilted track (Parts B & C) as it was for the level track (Part
A). Assume that this force can be modeled by f = N, where is the coefficient of friction and N is the normal
force. Use your calculation of f in Part A to determine , and calculate the friction force for the cart on the tilted
track. Was it a significant source of error to assume f had the same value on the tilted tracks as it did on the level
Explanation / Answer
part a) frictional force f=mv02/2s here no external force is acting except friction
use this formula for all the questions
here initialkinetic energy =1/2(mv2)