AP Physics 1hardmcq1 pt
Two blocks (4.0 kg and 2.0 kg) are stacked and pushed with 30 N on the bottom block over a frictionless floor (a = 5.0 m/s²). The horizontal force of the top block on the bottom block is
A.10 N
B.20 N
C.30 N
D.5.0 N
Explanation
Core Concept
The only horizontal force on the 2.0 kg top block is the contact force: F = ma = (2.0)(5.0) = 10 N, which acts backward on the bottom block by the third law.
Correct Answer
A10 N
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