physics question

Question

Besides its weight, a 3.70 kg object is subjected to one other constant force. The object starts from rest and in 1.20 s experiences a displacement of (4.70i hat - 3.30j) m, where the direction of j is the upward vertical direction. Determine the other force

 

_______i+______j

Answer 1

F_net = m Δv / Δt = m (v2 - v1) / Δt

 

v1 = 0

 

v2 = Δr / Δt = (4.7i - 3.3j) m / (1.2 s) = (3.92i - 2.75j) m/s

 

F_net = (3.7 kg) [(3.92i - 2.75j) m/s - 0] / (1.2 s) = (12.09i - 8.48j) N

 

F_net = F - (mg)j

 

F = F_net + (mg)j = (12.09i - 8.48j) N + (3.7 kg)(9.8 m/s^2)j = (12.09i + 27.78j) N