Question

Alejandra is attempting to drag her 38.4-kg Golden Retriever across the wooden floor by applying a horizontal force. What force (in newtons, N) must she apply to move the dog with a constant speed of 0.77 m/s? The coefficient of friction between the dog and the floor is 0.77. (Use the approximation that g ≈ 10 m/s^2)Answer: _________ N

Answer 1

u= coefficient of friction = 0.77

g= gravity = 10 m/s^2

m= mass = 38.4 kg

v= speed = 0.77 m/s

Apply Newton's second law:

Sum of forces = mass x acceleration

Net Force = f - umg

a = 0 (constant speed)

F = umg = 0.77 x 38.4 x 10 = 295.68 N