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An object with mass m = 10kg is still on the horizontal plane and starts to move under the action of horizontal constant force F = 20n The acceleration of gravity g = 10m / S2 (1) if the horizontal plane is smooth, calculate the acceleration A1 and the velocity at the end of 2 seconds (2) if the horizontal plane is rough and the dynamic friction coefficient between the object and the horizontal plane is 0.1, calculate the acceleration A2
（1）：F=ma,20=10*a,a1=2m/s^2 t=2,v=at,v=4m/s
(2):u=0.1 ,f=umg=10N,F-f=ma,a2=1m/s^2
F is the pulling force, M is the mass, a is the acceleration, t is the time, V is the velocity, u is the dynamic friction coefficient, f is the friction, G is the acceleration of gravity
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