A body pulled by a constant force accelerates from 10 cm/s to 35 cm/s in 3.5 s. A second force accelerates the same body from rest to 110 cm/s in 10.5 s. If the first force is known to be 5.0 N, that what is the second force?

The ratio of forces, F2/F1, equals the ratio of accelerations, so

F2/5.0 = [110/10.5]/[25/3.5]

Solve for F2