A constant friction force of 10 N acts on a 85 kg skier for 20 s. What is the skier's change in velocity?
force*time=mass*velocitychange
6.4 m/s
24
To find the skier's change in velocity, we can use Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. The equation is given as:
F = m * a
Where:
F is the net force applied,
m is the mass of the object, and
a is the acceleration of the object.
In this case, the friction force is the net force acting on the skier. Therefore,
F = 10 N (the friction force)
We need to rearrange the equation to solve for acceleration:
a = F / m
Substituting the given values:
a = (10 N) / (85 kg) = 0.118 m/s²
Now that we have the acceleration, we can use another equation of motion to find the change in velocity. The equation is:
v = u + at
Where:
v is the final velocity,
u is the initial velocity,
a is the acceleration, and
t is the time interval.
Given that the initial velocity of the skier is 0 m/s (assuming the skier starts from rest), and the time interval is 20 s, we can solve for the final velocity (change in velocity):
v = (0 m/s) + (0.118 m/s² * 20 s) = 2.36 m/s
Therefore, the skier's change in velocity is 2.36 m/s.