A sledge loaded with bricks has a total mass of 17.8 kg and is pulled at constan
ID: 1329971 • Letter: A
Question
A sledge loaded with bricks has a total mass of 17.8 kg and is pulled at constant speed by a rope inclined at 20.3 degree above the horizontal. The sledge moves a distance of 19.7 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500. What is the tension in the rope? v 67.88 Your response differs from the correct answer by more than 10%. Double check your calculations. N How much work is done by the rope on the sledge? kJ What is the mechanical energy lost due to friction? kJExplanation / Answer
let the tension in the rope is T
mass of sledge , m = 17.8 Kg
theta = 20.3 degree
distance , d = 19.7 m
a)
for the sledge to move with constant speed ,
N = mg - T * sin(20.3)
T*cos(20.3) = 0.50 *N
T*cos(20.3) = 0.50 *(17.8 * 9.8 - T * sin(20.3))
solving for T
T = 78.4 N
the tension in the rope is 78.4 N
b)
work done by rope = T * cos(20.3) * d
work done by rope = 19.7 * 78.4 * cos(20.3)
work done by rope = 1448.55 J
the work done by rope is 1448.55 J
c)
as the sledge moves with constant velocity
mechnical energy lost to friction = - 1448.55 J