Question

Below are birds-eye views of six identical toy cars moving to the right at 2 m/s. Various forces act on the cars with magnitudes and below. All forces act in the horizontal plane and are either parallel or at 45 or 90 degrees to the car's motion. Rank these cars on the basis of their speed a short time after the forces are applied. Rank from largest to smallest. To rank items as equivalent, overlap them.

Answer 1

Mass is constant and is kept as M.
car1: F=ma
10=ma
a=10/m

Car2:
Net force = 10-(2*5/√2)
               =2.93
a=2.93/m

Car3:all forces are in vertical, so no horiz acc.
a=0

Car4:F=0, ∴a=0;

Car5:Net force =10/√2-5
                       =2.07 backwards
a=-2.07/m (deceleration)

Car6:net force =10-10 =0
a=0;

Therefore after a small time period say Δt, the car with themost acceleration will have the most speed.
ranking them(largest to smallest):
1,2,(3,4,6),5 (where 3,4, and 6 have the samevelocity)