Question

(d) You observe someone pulling a block of mass 40 kg across a low-friction surface. While they pull a distance of 4 m in the direction of motion, the speed of the block changes from 5 m/s to 6 m/s. Calculate the magnitude of the force exerted by the person on the block. F

Answer 1

55 N

Step-by-step 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:

`v^2 = v_0^2+2as`

`v_0` and v are the initial and final velocities, a is the acceleration and s is the distance.

`a = (v^2-v_0^2)/(2s) = (6^2-5^2)/(2* 4) = (11)/(8) \text{ m/s}^2`

The force exerted on the block, assuming no friction, is

`F = ma = 40*(11)/(8) = 55\text{ N}`