Question

A 12 kg sled slides down a hill and collides inelastically with an 8 kg block at rest at the bottom of the hill (the sled and block stick together). There is no friction on the hill but the coefficient of friction on the flat ground is µ = .75. The sled and block slide for 2.5 meters along the flat ground before stopping. Calculate the following:

1. What is the frictional force between the sled & block (stuck together) and the flat
ground?

Answer 1

Step-by-step explanation:

The frictional force between the sled and block (stuck together) and the flat ground can be calculated using the formula:

friction = coefficient of friction * normal force

The normal force is the force exerted on an object perpendicular to the surface it is in contact with, and it can be calculated by using the weight of the object (mg). In this case, the weight of the sled and block (stuck together) is 12 kg + 8 kg = 20 kg. So, the normal force is 20 kg * 9.8 m/s^2 = 196 N.

Using the coefficient of friction provided (µ = .75), we can calculate the frictional force as:

friction = .75 * 196 N = 147 N.

So, the frictional force between the sled and block (stuck together) and the flat ground is 147 N.

Answer 2

To calculate the frictional force between the sled & block (stuck together) and the flat ground, we can use the equation:

friction = friction coefficient * normal force

The normal force is equal to the gravitational force acting on the combined mass of the sled and block, which is 12 kg + 8 kg = 20 kg. The gravitational force is equal to the mass multiplied by the acceleration due to gravity (g = 9.8 m/s^2).

So the normal force = 20 kg * 9.8 m/s^2 = 196 N

The coefficient of friction (µ) is given as 0.75. So the frictional force is:

friction = 0.75 * 196 N = 147 N

So the frictional force between the sled & block (stuck together) and the flat ground is 147 N.

Note that in calculating the normal force, we are assuming that the sled and block are moving as a single unit and therefore the force is acting on their combined mass. Also the force is calculated on the basis of friction coefficient which is given as 0.75