Answer:
Mass of Little Sister = 44.17 kg
Explanation:
From Newton's second law of motion, the magnitude of force applied on the sled is given by the following formula:
F = ma
where,
F = Force Applied = 120 N
a = Acceleration = 2.3 m/s²
m = Mass of Sled + Mass of Little Sister = 8 kg + Mass of Little Sister
Therefore,
120 N = (2.3 m/s²)(8 kg + Mass of Little Sister)
(120 N)/(2.3 m/s²) = 8 kg + Mass of Little Sister
Mass of Little Sister = 52.17 kg - 8 kg
Mass of Little Sister = 44.17 kg