Honors Physics

1
Honors Physics

• Inclined Plane
• Quiz
• 11/21/05

2
State the problem

• A 0.491 kg cart is on an inclined plane angled at
  27.50. The cart is connected via a string over
  a low friction pulley at the top of the inclined
  plane to a suspended mass of 0.21 kg. What is
  the acceleration of the cart when released?
  Ignore friction.
• From viewing the apparatus, the cart accelerates
  down the inclined plane.

3
State the problem
4
State the problem
m1
m2
5
Make a drawing
m10.491 kg
m20.21 kg
27.50
6
Make a free body diagram
We can treat this as an applied force since we
dont need tension.
Since we dont need to find the tension in the
cord we can essentially eliminate the need to sum
the forces on the hanging mass and just deal with
the mass on the inclined plane.
7
Make a free body diagram
Put weight into its components
FN
FN m1g cos ?
FT m2g
27.50
8
Sum the Forces
Note We are using total mass here because we
only wanted acceleration and not tension in the
cord. If we had wanted tension, then we would
have had two equations and the summation of forces
9
Solve for acceleration
Swap sides
Remember the total mass that is accelerating is
both the cart and the hanging mass
Note Since this is frictionless we didnt use
the Normal force nor the perpendicular component
of weight on the inclined plane in any
calculations.
10
Solve for acceleration
Substitute numbers and solve
Note that if you had not seen the cart go down
the incline, and the result was negative then you
could conclude that the cart went up the incline
when released.