Answer:
55 N
Explanation:
We find the acceleration of the block. The velocity changed from 5 m/s to 6 m/s in a distance of 4 m. We use the equation of motion:
[tex]v^2 = v_0^2+2as[/tex]
[tex]v_0[/tex] and v are the initial and final velocities, a is the acceleration and s is the distance.
[tex]a = \dfrac{v^2-v_0^2}{2s} = \dfrac{6^2-5^2}{2\times 4} = \dfrac{11}{8} \text{ m/s}^2[/tex]
The force exerted on the block, assuming no friction, is
[tex]F = ma = 40\times\dfrac{11}{8} = 55\text{ N}[/tex]
