Chapter 4, Problem 20TE

What is the acceleration of the stone in Think and Explain $19$ at the top of its path?

To determine

The acceleration of the stone at the top of its path.

Answer to Problem 20TE

The acceleration of the stone at the top of its path is $-9.81{\text{m/s}}^2$.

Explanation of Solution

When the stone is going up, it experience two forces, weight of the stone acting downward and tension in the string acting upwards. Since, the stone is accelerated upwards, there must be a net upward force acting on the stone. So, the tension in the string must be greater than weight of the stone.

When the stone is moving up, the net acceleration acting on it is $9.81{\text{m/s}}^2$, which slows down a moving stone's speed. When it is reached at the maximum height, its velocity becomes zero, which means that the net acceleration of acting on the stone becomes $-9.81{\text{m/s}}^2$ that cancels the effect of the gravitational pull of the earth.

Conclusion:

Therefore, the acceleration of the stone at the top of its path is $-9.81{\text{m/s}}^2$.