Heat = m x c x Δθ
2000 = 2 x c x 5
Specific heat c = 200 J / Kg / C
Answer:
a) 
b) 
Explanation:
Given the information from the exercise we can calculate the work done by the elevator using the following formula:

a) Considering you and your belongings as a system we know that the elevator is applying a Normal reaction force of:

Since the force applied and the displacement is in the same direction, the work done by the elevator is positive

b) The reaction force applied by the elevator is the same as the weight of the person

Since the force applied and the displacement is in opposite direction, the work done by the elevator is negative

The formulas used to analyze the horizontal and vertical motion of projectiles launched at an angle involve the use of tangent, cosine and sine.
<h3>
What is vertical motion of a projecile?</h3>
The vertical motion of a projectile is affected by gravity and the velocity of vertical motion given by the following formula;
Vy = Vsinθ
<h3>
What is horizontal motion of a projecile?</h3>
The horizontal velocity of a projectile is given by the following formula;
Vx = Vcosθ
<h3>Direction of the motion</h3>
The direction of the motion is calculated as follows;
tanθ = Vy/Vx
Thus, the formulas used to analyze the horizontal and vertical motion of projectiles launched at an angle involve the use of tangent, cosine and sine.
Learn more about vertical motion here: brainly.com/question/24216590
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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:
Explanation:
I think the answer is statement no 3.
Hope it helps.