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huybinhs
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Homework Statement
Two crates rests on the floor, one next to the other. A man pushes with a horizontal force of 400 N on the larger (50.0 kg) crate, which, in turn, pushes the other (25.0 kg) so that both slide as he walks along. Each crate experiences a friction force opposing the motion equal to 40% of its weight.
1.Determine the acceleration of the crates.
Answer in m/s^2
2.What is the force exerted by one crate on the other?
Answer in Newtons
Homework Equations
andThe Attempt at a Solution
1) total friction force Ff = 40 x (50+25) x 9.8/100 = 294 N
=>F(net) = F(applied) - Ff
=>F(net) = 400 - 294 = 106 N
=>By F = ma
=>106 = 75 x a
=>a = 106/75 = 1.41 m/s^2 => CORRECT
2)F(net) = 106 N => INCORRECT. Why? Please help!