Two blocks,joined by a string,have masses of 3.0 and 4.0 kg.They rest on a frictionless horizontal surface.A second string,attached only to the 4.0-kg block,has horizontal force = 40 N applied to it.Both blocks accelerate.Find the tension in the string between the blocks.
A)23 N
B)5.7 N
C)17 N
D)93 N
E)120 N

Question

Quizplus · Accepted Answer

First, we need to find the acceleration of the blocks. Since they are connected by a string, they will have the same acceleration. We can use Newton's second law to find the acceleration:

F = ma
40 N = (3 kg + 4 kg) a
a = 5 m/s^2

Now that we know the acceleration, we can find the tension in the string between the blocks. We can use the equation:

T - m1g = m1a
T - (3 kg)(9.8 m/s^2) = (3 kg)(5 m/s^2)
T = 17 N

Therefore, the tension in the string between the blocks is 17 N (choice C).

Two Blocks,joined by a String,have Masses of 3