Answer:
96%
Explanation:
To find the values of the motor efficiency you use the following formula:

P_o: output power = 864J/0.5min=864J/30s=28.8W
P_i: input power = I*V = (3A)(12V) = 36W
By replacing this values you obtain:

hence, the motor efficiency is about 96%
traslation:
Pentru a găsi valorile eficienței motorului, utilizați următoarea formulă:
P_o: putere de ieșire = 864J / 0.5min = 864J / 30s = 28.8W
P_i: putere de intrare = I * V = (3A) (12V) = 36W
Înlocuind aceste valori obțineți:
prin urmare, eficiența motorului este de aproximativ 96%
Answer: Part(a)=0.041 secs, Part(b)=0.041 secs
Explanation: Firstly we assume that only the gravitational acceleration is acting on the basket ball player i.e. there is no air friction
now we know that
a=-9.81 m/s^2 ( negative because it is pulling the player downwards)
we also know that
s=76 cm= 0.76 m ( maximum s)
using kinetic equation

where v is final velocity which is zero at max height and u is it initial
hence


now we can find time in the 15 cm ascent


using quadratic formula

t=0.0409 sec
the answer for the part b will be the same
To find the answer for the part b we can find the velocity at 15 cm height similarly using

where s=0.76-0.15
as the player has traveled the above distance to reach 15cm to the bottom


when the player reaches the bottom it has the same velocity with which it started which is 3.861
hence the time required to reach the bottom 15cm is

t=0.0409
We Know, F = m*a
Here, F = 34 N
m = 213 Kg
Substitute their values in the equation,
34 = 213 * a
a = 34/213
a = 0.159 m/s²
So, your final answer & the acceleration of the object would be 0.159 m/s²
Hope this helps!
Explain a police role, and how important it is. also you can explain a mayor's role and how important it is...
A police's role in the community is to protect us and make sure that everyone is following the rules. it is important for a police to be there so we can be safe. Their status is fair enough. Another Example is a mayor. a mayor's job is to improve the city/ the community. His status is high. There are many people around us that help us, each with a different status.
**Tell me if you need more