Aball on the end of a rope is moving in a vertical circle near the surface of the earth. point a is at the top of the circle; c is at the bottom. points b and d are exactly halfway between a and c. which one of the following statements concerning the a boy is whirling a stone at the end of a string around his head. the string makes one complete revolution every second, and the tension in the string is ft. the boy increases the speed of the stone, keeping the radius of the circle unchanged, so that the string makes two complete revolutions per second. what happens to the tension in the sting?

Tension in the string will increase

Explanation:

As we know that tension in the string at any angle with the vertical is given as

now we have

also we know that

angular speed of the stone is directly depending on the time period of the motion

so it is given as

since the frequency of the revolution is increased from n = 1 rev/s to 2 rev/s

so the angular speed would be doubled

So here we can say that

tension in the string will increase when we will increase the frequency of revolution.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.