Answer:
Step-by-step explanation:
The weight of the wheelbarrow will act downwards . Its component parallel to the plank will act downwards along the plank .
The value of component = mgsinθ
21.6 x 9.8 x sin20
= 72.4 N
The person shall have to apply force equal to this component so that the barrow moves with uniform velocity.
Force required = 72.4 N .