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:
B
Explanation:
Because this oscillations occur when the restoring force is directly proportional to displacement, given as
F=-kx
Where k= force constant
X= displacement
What Is A Molecule? B) NaCi
Answer: 90 kgm/s
Explanation:
The momentum (linear momentum)
is given by the following equation:
Where:
is the mass of the skater
is the velocity
In this situation the skater has two values of momentum:
Initial momentum: 
Final momentum: 
Where:


So, if we want to calculate the difference in the magnitude of the skater's momentum, we have to write the following equation(assuming the mass of the skater remains constant):
Finally:
Answer:
a. The moment of the 4 N force is 16 N·m clockwise
b. The moment of the 6 N force is 12 N·m anticlockwise
Explanation:
In the figure, we have;
The distance from the point 'O', to the 6 N force = 2 m
The position of the 6 N force relative to the point 'O' = To the left of 'O'
The distance from the point 'O', to the 4 N force = 4 m
The position of the 4 N force relative to the point 'O' = To the right of 'O'
a. The moment of a force about a point, M = The force, F × The perpendicular distance of the force from the point
a. The moment of the 4 N force = 4 N × 4 m = 16 N·m clockwise
b. The moment of the 6 N force = 6 N × 2 m = 12 N·m anticlockwise.