Question

Two masses are attached to a string that is hung over a pulley. m1 has a mass of 3.0 kgand is accelerating downward at 4.9 m/s^2. What is the tension in the string and themass of m2?

Answer 1

m1= 3 kg

a = 4.9 m/s^2

Apply newton's second law:

∑F = m*a

For m1:

m1g + T = m1 * a

g= gravity = 9.8 m/s^2

3 (9.8) + T = 3 (4.9 )

29.4 + T = 14.7

29.4 + 14 .7 = T

T = 44.1 N

For m2

m2g - T = m2(- a)

m2 (9.8) - 44.1 = m2 (-4.9)

9.8m2 + 4.9 m2 = 44.1

14.7 m2 = 44.1

m2= 44.1 /14.7

m2= 3 kg