Abby is swinging a ball on a string in a circle with a constant tension. Which of the following quantities is constant?
a. acceleration
b. speed
c. none of the others
d. velocity
e. force
speed if the circle is horizontal.
If vertical circle, none are constant.
B, speed
In this scenario, Abby is swinging a ball on a string in a circle with a constant tension. We need to determine which quantity remains constant throughout the motion.
To find the correct answer, let's analyze each of the options:
a. acceleration: Acceleration is the rate at which velocity changes. In this case, because Abby is swinging the ball in a circle, the velocity is constantly changing direction. Therefore, the acceleration is not constant.
b. speed: Speed is the rate at which an object covers distance. Since Abby is swinging the ball with a constant tension, the length of the string remains the same throughout the motion. As a result, the distance covered by the ball each second remains constant. Therefore, the speed is constant.
c. none of the others: This option implies that none of the mentioned quantities remain constant. However, as we discussed earlier, the speed does remain constant in this scenario.
d. velocity: Velocity is a vector quantity that includes both the speed of an object and its direction. Since the ball is swinging in a circle, the direction of the velocity constantly changes. Therefore, the velocity is not constant.
e. force: The tension in the string provides the necessary force to keep the ball moving in a circular path. However, this force is not constant as it depends on the tension applied by Abby and the centripetal force required to maintain the circular motion. Therefore, the force is not constant.
From the above analysis, we can conclude that the only quantity that remains constant in this scenario is the speed (option b).