Question

A horizontal force of 200 N is needed to pull a 70 kg box across the horizontal floor at constant speed. Calculate is coefficient of friction between box and floor.... ​

Answer 1

Answer:

(b) Frictional force acting on the box,

F=μmg=0.25×20×9.8=49N

This force must be same as applied force F so that the box moves with constant speed. Work done by the applied force, F

W=Fs=49×2=98J

Answer 2

Answer:

0.291 is the coefficient of friction.

Explanation:

Given :-

• horizontal force = 200 N
• mass of box = 70 kg
• acceleration due to gravity = 9.8 m/s^2

Frictional force acting on the box,

$F=μmg$

$200 N = μ×70×9.8$

$μ = \frac{200 }{70 \times 9.8}$

$μ =0.291$

therefore , the coefficient of friction between box and floor = 0.291