Question

Two weights are connected by a massless wire and pulled upward with a constantspeed of 1.50 m/s by a vertical pull P. The tension in the wire is T(see figure). Whichone of the following relationships between Tand Pmust be true?

A)T

B)T=P
C)P+T=125N
D)P=T+25N

Answer 1

Answer:

C T=P is the right answer

Answer 2

Given: Two weights are connected by a massless wire and pulled upward with a constant speed of 1.50 m/s by a vertical pull P. The tension in the wire is T(see figure).

To find: The correct relationship between T and P.

Solution:

The tension in the wire acts downwards due to the 100 N load which is acted upon acceleration due to gravity. The 25 N load also acts downwards because of the acceleration due to gravity. Since the vertical pull is upwards, the force P acts upwards.

According to the principle of conservation of energy, the force applied upwards must be equal to the force applied downwards. Hence,

$P = T + 25$

Therefore, the correct relationship between T and P is D)P=T+25N.