Question

An individual performs two drop landings from the exact same height above two different basketball floors. The first landing is onto a suspended basketball floor (hardwood suspended above the concrete/ground). The second landing is onto a traditional basketball floor (hardwood on the concrete/ground). The net vertical force acting on the individual to bring them to a stop would be ____ because the ____.

Group of answer choices

greater during the first landing : displacement along the line of action of the force would be less

the same during both landings : change in mechanical energy would be the same

less during the second landing : displacement along the line of action of the force would be greater

greater during the second landing : displacement along the line of action of the force would be less

less during the first landing : change in mechanical energy would be less

Answer 1

Potential energy is given by: mgh, where m is mass, g is gravitational acceleration and h is height.

In the given problem, drop landings are performed from the same height. So, initial potential energy is same.

Using law of conservation of energy, final kinetic energy=initial potential energy

=>final kinetic energy is same in both cases.

Also, final height is same in both cases, which implies, final potential energy is also same.

So,final mechanical energy(=kinetic energy+potential energy) is same for both cases.

Work done=Fs , where F is force and s is displacement along the direction of force F..

Now, work done by the normal force=change in mechanical energy.

Since change in mechanical energy is same in both cases, work done by the normal force should be same.

In the second landing, displacement s is less. Since work done is same for both cases, force F has to be greater for the second case.

So, the answer is : greater during the second landing :displacement along the line of action of force would be less.