Amy is in-line skating. Her mass is 50 kg. She is rolling forward (north) on a flat section of road at 10 m/s. The rolling friction acting on the wheels of her skates is 10 N backward (south). Air resistance creates a 15 N force also acting backward (south) on her. If these are the only horizontal forces acting on Amy. What is her horizontal acceleration as a result of these forces?

The right solution is "0.50 m/s²". A further explanation is provided below.

Explanation:

The given values are:

Mass,

m = 50 kg

Speed,

v = 10 m/s

Rolling friction acting backward (south),

f = 10 N

Air resistance acting backward (south),

= 15 N

The total force acting will be:

⇒  

On substituting the given values, we get

⇒      

⇒      

Now,

⇒  

On substituting the given values, we get

⇒    

⇒    

The horizontal acceleration will be "0.50 m/s²" because the (-)ve sign indicates it in south direction.

b would be the answer