Suppose a 49-N sled is resting on packed snow. The coefficient of kinetic friction is 0.10. If a person weighing 585 N sits on the sled, what force is needed to pull the sled across the snow at constant speed
Total weight = 49 + 585
so
pulling force = 0.1(49+585)
To find the force needed to pull the sled across the snow at a constant speed, we need to consider the forces acting on the sled.
1. The force of gravity (weight) acting on the sled is given by the formula:
Weight = mass × acceleration due to gravity
In this case, the weight of the sled is 49 N.
2. The force of friction between the sled and the snow is given by the formula:
Friction = coefficient of friction × normal force
The normal force is equal to the weight of the sled plus the weight of the person sitting on it.
Normal force = weight of sled + weight of person = 49 N + 585 N = 634 N
Now, since the sled is moving at a constant speed, we know that the force applied to pull the sled must be equal to the force of friction. If the force applied is greater than the force of friction, the sled would accelerate, and if the force applied is less than the force of friction, the sled would decelerate.
Therefore, the force required to pull the sled at a constant speed is equal to the force of friction:
Force required = Friction = coefficient of friction × normal force
Plugging in the values:
Force required = 0.10 × 634 N = 63.4 N
Hence, a force of 63.4 N is needed to pull the sled across the snow at a constant speed.