A block of weight 7.0N rest on a level floor. The frictional force between the block and the floor is 1.0N. A horizontal force of 1.4N is used to pull the block for 4seconds. What is the velocity of the block after this time

2 answers

acceleration = net force / mass = (1.4 N - 1.0 N) / (7.0 N / g) ... m/s^2

velocity = acceleration * time
F = 1.4 N., Ff = 1 N.
Mg = 7, M = 7/g = 7/9.8 = 0.71 kg. = Mass of the block.

F-Ff = M*a.
1.4-1 = 0.71a
a = 0.56 m/s^2.

V = Vo+a*T = 0+0.56*4 = __ m/s.