A 15 kg sled experiences an applied force of 5.5 N [north] and an opposing frictional force of 2.5 N [south]. If the sled starts from rest, what will be the velocity of the sled after 4.0 s?
a = F/m = (5.5-2.5)/15 = 0.20 m/s^2.
V = Vo + a*t = 0 + 0.2*4 = 0.8 m/s.
To determine the velocity of the sled after 4.0 s, we need to use Newton's second law of motion:
F_net = ma
Where F_net is the net force acting on the sled, m is the mass of the sled, and a is the acceleration of the sled.
First, let's calculate the net force acting on the sled:
F_net = F_applied - F_friction
F_net = 5.5 N [north] - 2.5 N [south]
Since the forces are in opposite directions, we need to subtract them:
F_net = 5.5 N - (-2.5 N)
F_net = 5.5 N + 2.5 N
F_net = 8.0 N [north]
Now, we can calculate the acceleration using Newton's second law:
F_net = ma
8.0 N = 15 kg * a
Solving for a:
a = 8.0 N / 15 kg
a = 0.533 m/s² [north]
Since the sled starts from rest, the initial velocity (u) is 0 m/s.
Next, we can use the equations of motion to find the final velocity (v):
v = u + at
Substituting the given values:
v = 0 m/s + (0.533 m/s²) * 4.0 s
v = 0 m/s + 2.132 m/s
v = 2.132 m/s
Therefore, the velocity of the sled after 4.0 s will be 2.132 m/s [north].