According to a certain estimate, the depth n(t), in centimeters, of the water in a certain tank at t hours past 2: 00 in the morning is given by n(t)= -20(t - 5)^2 + 500 for 0 ≤ t ≤ 10. according to this estimate, at what time in the morning does the depth of the water in the tank reach its maximum? a) 5: 30 b) 7: 00 c) 7: 30 d) 8: 00 e) 9: 00

b) 7.00

Explanation:

N( t ) = -20( t - 5 )²

dN/ dt = -20 x 2 ( t - 5 )

For maximum N ( depth )

dN/dt = 0

- 40 ( t - 5 ) = 0

t = 5

So at 2 + 5 = 7 .00 am depth of water reaches its maximum.

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

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.