Kylie asked in Science & MathematicsPhysics · 7 months ago

Physics Help!!!!?

1. An object of mass 2.6 kg that is initially at rest is accelerated by a constant force.  After the force acts on the object over a distance of 2.1 m, the speed of the object is 5.5 m/s.  What is the magnitude of the force in newtons?  

2. A block slides on a horizontal surface with an initial speed of 22 m/s.   If the block takes 4  s to come to a stop, what is the coefficient of kinetic friction, μk between the block and the surface?  Take g = 10 m/s2. 

1 Answer

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  • 7 months ago

    first find the acceleration

    v² = v₀² + 2ad

    5.5² = 0² + 2a(2.1)

    a = 30.25/4.2 = 7.20 m/s²

    now use F = ma

    F = 2.6•7.2 = 20.2 N

    2) first find the acceleration

    a = Δv/Δt = 22/4 = 5.5 m/s²

    F = ma = 5.5m N

    weight of block w = mg = 10m

    μk = F/w = 5.5m/10m = 0.55

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