Answer:
The ball's kinetic energy is a. 10 J
Explanation:
Conservation of Mechanical Energy
In an isolated system is subject only to conservative forces, then the mechanical energy is constant.
The mechanical energy is calculated as:
E=K+U
Where K is the kinetic energy and U is the gravitational potential energy.
The gravitational potential energy of the body of mass m can be calculated by:
U=m.g.h
Recall m.g is the weight of the body, thus:
U=W.h
Where h is the height of the object.
The kinetic energy is calculated as:
[tex]\displaystyle K=\frac{1}{2}m.v^2[/tex]
Where v is the speed of the object.
Initially, the bowling ball is at rest at a height of 5 m. Its gravitational potential energy is:
U1=10*5=50\ J
The kinetic energy is zero since v=0.
Thus the initial mechanical energy is:
E=50 J + 0 J = 50 J
When the object falls 1 m, its height is h=4 m. The new gravitational potential energy is:
U2=10*4=40 J
Since the mechanical energy is constant:
U2 + K2 = 50 J
Solving for K2:
K2 = 50 J - 40 J
K2 = 10 J
The ball's kinetic energy is a. 10 J
