Final answer:
The skier's change in velocity due to a 19 N friction force acting over 25 s is 8.64 m/s. This represents the skier slowing down over the given period.
Step-by-step explanation:
To calculate the skier's change in velocity, we can use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration (F = ma). Given a constant friction force of 19 N acting over a time of 25 s on a 55-kg skier on level snow, we can first find the skier's acceleration due to friction. Since friction is the only force acting horizontally, we can say:
Ffriction = m * a
19 N = 55 kg * a
a = 19 N / 55 kg
= 0.3455 m/s²
To find the change in velocity, we use:
Δv = a * t
Δv = 0.3455 m/s² * 25 s
= 8.6375 m/s
Therefore, the skier's change in velocity due to the friction force is 8.64 m/s (two significant figures). It is important to realize this change would slow down the skier if the original velocity was higher than this value,
Your question is incomplete, but most probably your full question was
A constant friction force of 19 N acts on a 55-kg skier for 25 s on level snow. What is the skier's change in velocity? Express your answer to two significant figures and include the appropriate units.