Question

Two masses are joined by a massless string. A 30-N force applied vertically to the upper mass gives the system a constant [Ans : 490 N] [Ans : 1.3 × 10−23 m] [Ans : 19 cm] [Ans : 1.96 ms−2 ] [Ans : 680 m] upward acceleration of 3.2 m/ s 2 . If the string tension is 18 N, what are the two masses?

Answer 1

Answer:

12/13 kg, 18/13 kg

Explanation:

Let the masses are m and m'.

acceleration, a = 3.2 m/s^2

Force, F = 30 N

Tension, T = 18 N

By the diagram, using Newton's second law

F - T - m'g = m' a .... (1)

T - mg = ma ..... (2)

Substitute the values of F, T and a in equation (1) and equation (2)

30 - 18 = m' (9.8 + 3.2)

12 = 13 m'

m' = 12/ 13 kg

And, 18 = m (9.8 + 3.2)

m = 18/13 kg