Question

Two blocks of masses 20 kg and 8.0 kg are connected together by a light string and rest on a frictionless, level surface. Attached to the 8.0-kg mass is a second light string, which a person uses to pull both blocks horizontally. If the two-block system accelerates at 1.0 m/s2, what is the tension in the second string attached to the 8.0-kg mass?

a. 6.0 N

b. 4.0 N

c. 14 N

d. 28 N

Answer 1

given

first mass m₁ = 20 Kg

second mass m₂ = 8 Kg

acceleration a = 1 m/sec²

using equation F = m a

or

F = ( m₁ + m₂ ) a

= ( 20 + 8 ) x 1

= 28 N

the the tension in the second string attached to the 8.0-kg mass m₂ is 28 N

Option " d " is correct.

Answer 2

The tension is from the 20 g mass acting on the 8 gram mass. So in the equation F=ma, the mass is 20g because that is what is contributing to the tension force. Thus, F= (20)(0.5)=10