A pendulum swings past it's pole 20 times in 18 seconds, what is the period of the pendulum?

0.9

Explanation:

If frequency equals the amount of oscillations in one second then 20/18 = f = 1.11  and to find period (T) then we use the equation T= 1/f or in this case 1/1.11 = 0.9

true tan speed = ang vel x radius

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.