Một vật dao động điều hòa dọc theo trục Ox (O là vị trí cân bằng) có phương trình: x = 2cos(2πt + π/2) (cm). Hỏi sau thời gian bao lâu thì vật đi được quãng đường 99 cm kể từ thời điểm ban đầu t = 0 ?

chemical properties of thing

scientific laws are the result of testing theories and proving them to be facts.

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.