The coefficient of kinetic friction for wood on wood is o.55. The coefficient of kinetic friction for wood on wood is 0.68. For a 3.5kg wood block being pulled horizontally:
a. what is the pull force needed to start the wood block moving on a wood floor?
b. how hard would you need to pull to keep it sliding at a constant velocity on a wood floor?
suspect STATIC is 0.68
.68 m g = starting Force
.55 m g = constant velocity Force
To calculate the pull force needed to start the wood block moving on a wood floor, we need to determine the force of friction acting on the block and overcome it.
a. To find the force of friction (F_f) acting on the block, we can use the equation:
F_f = μ_k * N
where μ_k is the coefficient of kinetic friction and N is the normal force.
The normal force (N) is the force exerted by a surface perpendicular to the surface supporting the object. In this case, the wood block is placed on a wood floor, so the normal force is equal to the weight of the block (mg):
N = m * g
where m is the mass of the block and g is the acceleration due to gravity (approximately 9.8 m/s^2).
Let's calculate the normal force (N):
mass (m) = 3.5 kg
acceleration due to gravity (g) ≈ 9.8 m/s^2
N = 3.5 kg * 9.8 m/s^2
N = 34.3 N
Now, let's calculate the force of friction (F_f) using the given coefficient of kinetic friction (μ_k = 0.55):
F_f = 0.55 * 34.3 N
F_f ≈ 18.87 N
Therefore, the pull force needed to start the wood block moving on a wood floor is approximately 18.87 Newtons.
b. To keep the wood block sliding at a constant velocity on a wood floor, we need to overcome the force of friction and counterbalance it.
The force required to keep the block sliding at a constant velocity is equal to the force of friction (F_f) acting on the block.
Using the given coefficient of kinetic friction (μ_k = 0.68), we can calculate the force of friction on the block using the same equation:
F_f = 0.68 * 34.3 N
F_f ≈ 23.35 N
Therefore, to keep the wood block sliding at a constant velocity on a wood floor, a force of approximately 23.35 Newtons would need to be applied.