Each of the four wheels of the vehicle weighs 40 lb and is mounted on a 4in diameter journal. The total weight of the vehicle is 960 lb, including wheels, and is distributed equally on all four wheels. If a force P = 16 lb is required to keep the vehicle rolling at a constant low speed on a horizontal surface, calculate the coefficient of friction which exists in the wheel bearings.

Question

Each of the four wheels of the vehicle weighs 40 lb and is mounted on a 4in diameter journal. The total weight of the vehicle is 960 lb, including wheels, and is distributed equally on all four wheels. If a force P = 16 lb is required to keep the vehicle rolling at a constant low speed on a horizontal surface, calculate the coefficient of friction which exists in the wheel bearings.

The answer I calcualted was 10 and I know that can't be correct because the coefficients of friction are always less than 1

Answer 1

Your suppostion about being less than one is incorrect. What if the object being moved were superglued to the surface. IT can be greater than one.

NOw, the prob.

Each bearing has 960/4 lb force vetically on it.
each bearing is getting 4lb force to maintain movement.

forcefriction=normal*mu
mu= 4/230

Answer 2

this still isn't the correct answer though. my book says that it's 0.204

Answer 3

To calculate the coefficient of friction in the wheel bearings, we need to consider the forces acting on the vehicle.

Let's break down the problem step by step:

Step 1: Calculate the weight supported by each wheel. Since the total weight of the vehicle is 960 lb and it is equally distributed on all four wheels, each wheel supports 960 lb / 4 = 240 lb.

Step 2: Calculate the normal force acting on each wheel. The normal force is equal to the weight supported by the wheel, which is 240 lb.

Step 3: Determine the force acting in the direction of motion. In this case, the force required to keep the vehicle rolling at a constant low speed is given as P = 16 lb.

Step 4: Calculate the coefficient of friction. The friction force can be calculated using the equation F_friction = u * F_normal, where u is the coefficient of friction and F_normal is the normal force. Rearranging the equation, we have u = F_friction / F_normal.

Given that the force required to keep the vehicle rolling is P = 16 lb and the normal force is F_normal = 240 lb:

u = 16 lb / 240 lb = 0.067

Therefore, the coefficient of friction in the wheel bearings is 0.067, which is less than 1 as expected.

Your calculated answer of 10 is incorrect. Please check your calculations again.