- #1
zoner7
- 90
- 0
Homework Statement
Two cubic blocks are in contact, resting on a frictionless horizontal surface. The block on the left has a mass of mL = 6.70 kg, and the block on the right has a mass of mR = 18.4 kg. A force of magnitude 112 N is applied to the left face of the left block, toward the right but at an upward angle of 30.0° with respect to the horizontal. It causes the left block to push on the right block. What are (a) the direction and (b) the magnitude of the force that the right block applies to the left block?
Potential answers for a:To the left at an angle 30 degrees down. To the right at an angle 30 degrees upwards. Directly to the left. Directly to the right.
The answer is directly to the left.
Answer for b: 71.1J
Homework Equations
Fnet = ma
The Attempt at a Solution
(I'm going to ignore the y-direction as it does not matter).
I made some free body diagrams and determined that the left block had forces Fcos(theta) - N acting acting on it. I set the acceleration equal to 0.
I said that the right block only had a positive N force acting on it. After setting the acceleration to 0, I realized that something was seriously wrong. How could the normal force be 0 in one equation but Fcos30 in the other
Thank you in advance for any help.