Suppose the height of the ramp is h1= 0.3 m, and the foot of the ramp is horizontal, and is h2= 1.00 m above the floor. What will be the horizontal distance traveled by the following four objects before they hit the floor? Assume that R= 12.7 mm in each case; assume that the density of steel is 7.8 g/cm^3; and assume that the density of aluminum is 2.7 g/cm^3.

a) A solid steel sphere sliding down the ramp without friction
b) A solid steel sphere rolling down the ramp without slipping.
c) A spherical steel shell with shell thickness 1.0 mm rolling down the ramp without slipping
d) A solid aluminum sphere rolling down the ramp without slipping.

There some formula given which summarize all the way down to
-2sqrt(h1h2) - sliding object
-1.690sqrt(h1h2) - rolling solid sphere
-1.549sqrt(h1h2) - rolling hollow sphere

but i don't think were suppose to use them since i don't get why we don't use the density of thickness of the sphere

To determine the horizontal distance traveled by each object before hitting the floor, you need to consider the energy conservation principle.

a) A solid steel sphere sliding down the ramp without friction:
Since there is no friction involved, the only force acting on the sphere is its weight. The potential energy of the sphere when it is at height h1 is converted to kinetic energy when it reaches height h2. The horizontal distance traveled by the sphere can be calculated using the equation:

d = sqrt(2gh1),

where g is the acceleration due to gravity (approximately 9.8 m/s^2). Substitute the given values of h1 and h2, and calculate the distance traveled.

b) A solid steel sphere rolling down the ramp without slipping:
When the sphere rolls without slipping, both rotational and translational kinetic energy are involved. The potential energy at height h1 is converted to both kinetic energy and rotational energy. To calculate the distance traveled by the sphere, you need to consider the rolling without slipping condition.

The equation to calculate the distance is:

d = (5/7) * sqrt(2gh1),

where g is the acceleration due to gravity. Substitute the given values of h1 and h2, and calculate the distance traveled.

c) A spherical steel shell with shell thickness 1.0 mm rolling down the ramp without slipping:
Similar to the solid steel sphere, a spherical steel shell with a shell thickness rolling down the ramp without slipping has both translational and rotational kinetic energy. The equation to calculate the distance is:

d = (10/7) * sqrt(2gh1),

where g is the acceleration due to gravity. Substitute the given values of h1 and h2, and calculate the distance traveled.

d) A solid aluminum sphere rolling down the ramp without slipping:
To calculate the distance traveled by a solid aluminum sphere rolling down the ramp without slipping, you can use the same equation as for the solid steel sphere rolling without slipping. However, you need to consider the difference in density between steel and aluminum. The equation becomes:

d = (5/7) * sqrt((2gh1)*(density of steel)/(density of aluminum)),

where g is the acceleration due to gravity. Substitute the given values of h1, h2, and the densities of steel and aluminum, and calculate the distance traveled.

To calculate the horizontal distance traveled by each object before hitting the floor, we need to consider the conservation of energy and the relationship between potential energy and kinetic energy.

a) A solid steel sphere sliding down the ramp without friction:
In this case, since the sphere is sliding without friction, its initial potential energy is converted entirely into kinetic energy when it hits the floor. The horizontal distance traveled can be calculated using the equation:
Distance = sqrt(2 * g * h2)
where g is the acceleration due to gravity (approximately 9.8 m/s²) and h2 is the height of the foot of the ramp (1.00 m).
Substituting the values:
Distance = sqrt(2 * 9.8 * 1.00) = 4.43 meters

b) A solid steel sphere rolling down the ramp without slipping:
When a solid sphere is rolling without slipping, its initial potential energy is converted into both translational kinetic energy and rotational kinetic energy. The horizontal distance can be found using the concept of the conservation of energy:
Distance = (7/10) * sqrt(2 * g * h2)
Substituting the values:
Distance = (7/10) * sqrt(2 * 9.8 * 1.00) = 3.10 meters

c) A spherical steel shell with shell thickness 1.0 mm rolling down the ramp without slipping:
For a hollow sphere rolling without slipping, the distance traveled can also be found using the conservation of energy concept:
Distance = (7/10) * sqrt(2 * g * h2)
Substituting the values:
Distance = (7/10) * sqrt(2 * 9.8 * 1.00) = 3.10 meters

d) A solid aluminum sphere rolling down the ramp without slipping:
Similar to the solid steel sphere, the horizontal distance can be found using the conservation of energy concept:
Distance = (7/10) * sqrt(2 * g * h2)
Substituting the values:
Distance = (7/10) * sqrt(2 * 9.8 * 1.00) = 3.10 meters

Please note that the density and thickness of the spheres do not affect the calculation of the horizontal distance traveled in these cases, as they are not directly related to the distance traveled before hitting the floor.

Time to fall for all objects is t = sqrt(1/4.9)

Now find the speeds of the different objects at the bottom.
For a) it's a simple mgh = 1/2mv^2 (h is the ramp height in this case)
For the other 3 cases mgh = 1/2mv^2 + 1/2I(omega)^2 The I's you'll have to look up, they're related to mass and radius of the objects (so you do need density). The omega is just v/r.
Hope that helps.