A cube of mass m1 = 6.8 kg is sitting on top of another cube of the same size and mass m2 = 0.7 kg while they are both in free-fall. Ignoring any air resistance, what is the magnitude of the normal force with which the bottom cube is acting on the top cube?
I've tried multiplying each by gravity(9.8) but nothing I'm doing is giving a correct answer
never mind it's 0, just seemed too simple
To find the magnitude of the normal force with which the bottom cube is acting on the top cube, you can apply Newton's second law of motion.
In this scenario, both cubes are in free-fall, which means they are experiencing the force of gravity acting downwards. However, the bottom cube is also supporting the weight of the top cube, which creates the normal force.
Let's break down the steps:
1. Find the weight force of each cube:
The weight force is given by the formula weight = mass x gravitational acceleration.
For the top cube: weight₁ = m₁ * g
For the bottom cube: weight₂ = m₂ * g
2. Determine the net force acting on the top cube:
Since the top cube is in free-fall, the net force acting on it is equal to its weight force: net force₁ = weight₁.
3. Calculate the normal force exerted by the bottom cube on the top cube:
The normal force is equal in magnitude but in the opposite direction to the net force₁ acting on the top cube: normal force₂ = - net force₁ = - weight₁.
So, the magnitude of the normal force with which the bottom cube is acting on the top cube is equal to the magnitude of the weight force of the top cube: |normal force₂| = |weight₁| = m₁ * g.
Plugging in the given values, we have:
|normal force₂| = 6.8 kg * 9.8 m/s² = 66.64 N.
Therefore, the magnitude of the normal force is approximately 66.64 N.
To solve this problem, we need to consider the forces acting on the cubes. Since they are in free-fall, the only forces at play are the gravitational force and the normal force.
Let's start with the top cube. Since it is in free-fall, the gravitational force acting on it can be calculated using the equation F = m * g, where F is the force, m is the mass, and g is the acceleration due to gravity.
For the top cube:
Mass (m1) = 6.8 kg
Gravitational force (F1) = m1 * g = 6.8 kg * 9.8 m/s^2
Now let's consider the bottom cube. Since the top cube is resting on it, there must be a normal force acting between them. The value of the normal force is equal in magnitude but opposite in direction to the force the top cube exerts on the bottom cube.
Therefore, the magnitude of the normal force (N) with which the bottom cube acts on the top cube is equal to the gravitational force acting on the top cube.
Magnitude of the normal force (N) = F1 = 6.8 kg * 9.8 m/s^2
By calculating the value, you will be able to find the correct answer.