You accidentally drop a cell phone, if the cellphone lands on a grassy lawn, is its momentum less, the same, or greater?
momentum at landing is same. Mass*veloctiy
When a cellphone is accidentally dropped and lands on a grassy lawn, its momentum remains the same. According to the law of conservation of momentum, the total momentum of an isolated system remains constant if no external forces act upon it.
To understand why the momentum remains the same, let's break it down step by step:
1. Before the cellphone is dropped, it has an initial momentum which depends on its mass and velocity.
- Momentum (p) = mass (m) x velocity (v)
2. When the cellphone is dropped, it starts falling towards the ground under the influence of the force of gravity. As it falls, its velocity increases due to the acceleration caused by gravity.
3. When the cellphone lands on the grassy lawn, it encounters an external force (exerted by the ground) which brings it to a stop. This force acts for a very short duration of time, known as the collision time.
4. During this collision time, the cellphone's momentum changes from its initial momentum to zero. However, the total momentum of the system (cellphone and Earth) remains constant, as no external forces act on the system.
In summary, although the cellphone's momentum changes from its initial value to zero during the collision with the grassy lawn, the total momentum of the system is conserved. Therefore, its momentum remains the same.