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QNEET-2024-Ph-161: NEET 2024 Physics - Class 11 NEET-2024-Ph-161 Solution: An object falls from a height of 10 m above the ground. After…
An object falls from a height of 10 m above the ground. After striking the ground it loses 50% of its kinetic energy. The height upto which the object can rebounce from the ground is: 7.5 m 10 m 2.5 m 5 m
Multiple Choice Options
- A 7.5 m
- B 10 m
- C 2.5 m
- D 5 m
Step-by-Step Verified Solution
To solve this problem, we need to consider the principles of energy conservation and the behavior of the object during the rebound. Let's break it down step-by-step:
1. When the object falls from a height of 10 m , it converts its potential energy to kinetic energy at the point of impact. The potential energy (PE) just before hitting the ground can be calculated using the formula:
P E = m g h
where:
m is the mass of the object
g is the acceleration due to gravity ( 9.8 m / s 2 )
h is the height ( 10 m )
The kinetic energy (KE) of the object just before impact is equal to the potential energy it had at the height of 10 m , because of the conservation of energy principle.
2. Upon hitting the ground, the object loses 50 % of its kinetic energy. Therefore, the kinetic energy after the impact is:
K E a f t e r i m p a c t = 1 2 K E b e f o r e i m p a c t
3. The object will now rebound to a height where its kinetic energy is converted back to potential energy. Let this height be h r e b o u n d . The potential energy at this rebound height is:
P E r e b o u n d = m g h r e b o u n d
Since the kinetic energy after the impact is 1 2 m g h , we set this equal to the potential energy at the rebound height:
1 2 m g h = m g h r e b o u n d
By canceling out the mass m and the gravitational constant g , we get:
1 2 h = h r e b o u n d
Substituting h = 10 m , we find:
1 2 _ 10 m = h r e b o u n d
h r e b o u n d = 5 m
Therefore, the height up to which the object can rebound from the ground is 5 m . The correct answer is:
Option D 5 m