Answer:
K = 960 J
Explanation:
Given that,
Mass of a child = 20 kg
Mass of a sled = 10 kg
Speed of child on sled = 8 m/s
We need to find the kinetic energy of the sled with the child.
The total mass of child and the sled = 20 kg + 10 kg
= 30 kg
The formula for the kinetic energy of an object is given by :
Hence, the kinetic energy of the sled with the child is 960 J.
Answer:
Explanation:
radius of hoop and the radius of disk is same = R
Let the mass of hoop is M and the mass of disk is M'.
As they reach the bottom of teh surface in same time so they travel equal distance thus, they have same acceleration.
The acceleration is given by
As the acceleration is same so that the moment of inertia is also same.
Moment of inertia of disk = moment of inertia of hoop
1/2 x mass of disk x R² = mass of hoop x R²
So, mass of disk = 2 x mass of hoop
Option (c) is correct.