Question
Physics Question on laws of motion
A uniform rope of length 4 m and mass 0.4kg is held on a frictionless table in such a way that 0.6m of the rope is hanging over the edge. The work done to pull the hanging part of the rope onto the table is, (Assuming g=10m/s2)
A
0.36J
B
0.24J
C
0.12J
D
0.18J
Answer
0.18J
Explanation
Solution
The portion of the chain hanging from the table can be determined using the equation: ��=120 cm�⇒�=103 xL =x 120 cm⇒ x =310
The work done in pulling the chain onto the table can be calculated using the equation: �=��ℎ(1−��)2=4×10×4×(103)2=72 J W =mgh(1− xL )2=4×10×4×(310)2=72J.
The answer, rounded to two decimal places, is 0.18 J.
The correct answer is option (D): 0.18J