Question

John is pushing a wheelbarrow with a sand on a buildingsite. The total mass of the wheelbarrow and it's contents is 30 kg . When he applies a force of 20N, the wheelbarrow moves forward at a constant speed. What is the magnitude of the friction between the wheels and the ground? Explain your answer.(20N)

Answer 1

Let the magnitude of friction force = f

acceleration ,a = 0 (because it moves with constant speed)

F=ma

20-f=30x0

f=20N